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Results for "Y. J. Chu"

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Comparison of room-temperature multiferroics in Bi4Fe2TiO12 film and bulkAug 18 2006Oct 27 2006It is reported that both dielectricity and magnetism at room temperature have been appreciably improved in Bi4Fe2TiO12 film compared with that of Bi4Fe2TiO12 bulk. X-ray diffraction profiles reveal similar crystalline nature and random orientation of ... More
Quasars around the Seyfert Galaxy NGC3516Dec 02 1997We report redshift measurements of 5 X-ray emitting blue stellar objects (BSO's) located less than 12 arc min from the X-ray Seyfert galaxy, NGC 3516. We find these quasars to be distributed along the minor axis of the galaxy and to show a very good correlation ... More
Search for exotic spin-dependent interactions with a spin-exchange relaxation-free magnetometerJun 02 2016Jul 28 2016We propose a novel experimental approach to explore exotic spin-dependent interactions using a spin-exchange relaxation-free (SERF) magnetometer, the most sensitive non-cryogenic magnetic-field sensor. This approach studies the interactions between optically ... More
Hot Interstellar Gas in the Irregular Galaxy NGC 4449Feb 13 1997NGC 4449 is an irregular galaxy with a moderately high star formation activity. The massive stars in NGC 4449 have given rise to many bright HII regions, superbubbles, supergiant shells, and "chimney-like" radial filaments. ROSAT X-ray observations of ... More
The dissolving Rosette HH2 jet bathed in harsh UV radiation of the Rosette NebulaFeb 21 2006Herbig-Haro flows discovered in photoionized medium forms a separate category and detailed studies of which become one of the key issues to our understanding of jet production and evolution. The Rosette HH2 jet is the second of such flows that immersed ... More
Search for an axion-induced oscillating electric dipole moment for electrons using atomic magnetometersSep 07 2018Feb 14 2019We propose an experimental search for an axion-induced oscillating electric dipole moment (OEDM) for electrons using state-of-the-art alkali vapor-cell atomic magnetometers. The axion is a hypothesized new fundamental particle which can resolve the strong ... More
Circumstellar Nebulae in Young Supernova RemnantsDec 29 2000Supernovae descendent from massive stars explode in media that have been modified by their progenitors' mass loss and UV radiation. The supernova ejecta will first interact with the circumstellar material shed by the progenitors at late evolutionary stages, ... More
Suspending superconducting qubits by silicon micromachiningJun 09 2016We present a method for relieving aluminum 3D transmon qubits from a silicon substrate using micromachining. Our technique is a high yield, one-step deep reactive ion etch that requires no additional fabrication processes, and results in the suspension ... More
VLT observations of the highly ionized nebula around Brey2Feb 25 2003We present the first high resolution HeII 4686 images of the high excitation nebula around the WR star Brey 2 in the LMC. This nebula presents a striking morphology: a small arc-like feature some 3.6pc in radius is particularly prominent in the HeII 4686 ... More
WR bubbles and HeII emissionJun 04 2003We present the very first high quality images of the HeII 4686 emission in three high excitation nebulae of the Magellanic Clouds. A fourth high excitation nebula, situated around the WR star BAT99-2, was analysed in a previous letter. Using VLT FORS ... More
Giant magnetoelectric effect under high bias fields in cylindrical bilayered Ni-PZT compositesAug 31 2007For conventional plate and disc layered magnetoelectric (ME) composites, the ME effect appeared under low bias magnetic fields, which caused by line magnetostriction. In this paper, we present a new structure ME composites, cylindrical bilayered composites. ... More
Superconductivity in the C32 Intermetallic Compounds AAl(2-x)Si(x), with A=Ca and Sr, and 0.6<x<1.2Aug 16 2002The intermetallic compounds AAl2-xSix, where A = Ca, Sr or Ba, crystallize in the C32 structure, same as the recently discovered MgB2 with a high superconducting transition temperature of 39 K. For x = 1, superconductivity has been observed in AAlSi with ... More
Shape demagnetization effect on layered magnetoelectric compositesAug 30 2007Magnetoelectric (ME) voltage coefficient was always considered independent on in-plane shape of plate layered magnetostrictive-piezoelectric composites due to the oversimplification in ME theoretical models. In this article, we present that in fact the ... More
Plasma-Like Negative Capacitance in Nano-ColloidsDec 06 2006A negative capacitance has been observed in a nano-colloid between 0.1 and 10^-5 Hz. The response is linear over a broad range of conditions. The low-omega dispersions of both the resistance and capacitance are consistent with the free-carrier plasma ... More
Field-induced giant static dielectric constant in nano-particle aggregates at room temperatureSep 20 2005The analogy between magnetism and electricity has long been established by Maxwell in the 19th century, in spite of their subtle difference. While magnetic materials display paramagnetism, ferromagnetism, antiferromagnetism, and diamagnetism, only paraelectricity, ... More
Separation Between Antiferromagnetic and Ferromagnetic Transitions in Ru_1-xCu_xSr_2EuCu_2O_8+dApr 07 2003The macroscopic magnetizations of Ru_1-xCu_xSr_2EuCu_2O_8+d with x between 0 and 0.15 were investigated. A ferromagnet-like transition as well as an antiferromagnet-like transition appear around T_M in the low-field magnetization and around T_AM in the ... More
Water Content and Superconductivity in Na0.3CoO2*yH2OAug 15 2003We report here the correlation between the water content and superconductivity in Na0.3CoO2*yH2O under the influences of elevated temperature and cold compression. The x-ray diffraction of the sample annealed at elevated temperatures indicates that intergrowths ... More
Spitzer Surveys of Infrared Excesses of White DwarfsDec 07 2010IR excesses of white dwarfs (WDs) can be used to diagnose the presence of low-mass companions, planets, and circumstellar dust. Using different combinations of wavelengths and WD temperatures, circumstellar dust at different radial distances can be surveyed. ... More
Spitzer Surveys of IR Excesses of White DwarfsDec 07 2010IR excesses of white dwarfs (WDs) can be used to diagnose the presence of low-mass companions, planets, and circumstellar dust. Using different combinations of wavelengths and WD temperatures, circumstellar dust at different radial distances can be surveyed. ... More
XMM-Newton observations of the giant HII region N11 in the LMCFeb 26 2004Using the sensitive XMM-Newton observatory, we have observed the giant HII region N11 in the LMC for \sim30 ks. We have detected several large areas of soft diffuse X-ray emission along with 37 point sources. One of the most interesting results is the ... More
A negative dielectric constant in nano-particle materials under an electric field at very low frequenciesNov 07 2005The significance of a negative dielectric constant has long been recognized. We report here the observation of a field-induced large negative dielectric constant of aggregates of oxide nano-particles at frequencies below ~ 1 Hz at room temperature. The ... More
Nonstoichiometry, Defects and Transport Properties in MgB2May 24 2001The local composition Mg:B of MgB2 powder was systematically changed through annealing. Correlations were observed between the Mg loss and the lattice parameters a/c and the microstrain of MgB2. Direct wavelength-dispersive-spectrum and XRD measurements ... More
Direct Observation of Coexistence of Ferromagnetism and Superconductivity in RuSr2(Gd0.7Ce0.3)2Cu2O10May 26 2001Recent reports of the detecting of ferromagnetism and superconductivity in ruthenium-cuprates have aroused great interest. Unfortunately, whether the two antagonistic phenomena coexist in the same space in the compounds remains unresolved. By employing ... More
Ni-PZT-Ni Trilayered Magnetoelectric composites Synthesized by Electro-depositionAug 30 2007We report the high strength of magnetoelectric (ME) coupling of trilayered composites prepared by electro-deposition. The ME coupling of Ni-lead zirconate titanate (PZT)-Ni trilayered structure was measured ranged from1 kHz to 120 kHz. The trilayered ... More
Magnetoelectric Effect in Ni-PZT-Ni Cylindrical Layered Composite Synthesized by Electro-depositionAug 30 2007The magnetoelectric (ME) coupling of cylindrical trilayered composite was studied in this paper. The Ni-lead zirconate titanate (PZT)-Ni trilayered cylindrical composite was synthesized by electro-deposition. The maximum ME voltage coefficient of cylindrical ... More
The bipolar structure of the LBV nebula around HR CarinaeFeb 22 1997HR Carinae is one of the few Luminous Blue Variables (LBVs) in the Galaxy. It has a nebula that appears bipolar. We have obtained imaging and high-dispersion, long-slit echelle data of the HR Car nebula, and confirmed that it is a bipolar nebula. Its ... More
Room-temperature delayed giant magnetodielectric effects observed in Bi4Fe2TiO12 filmJun 30 2006Jan 22 2013This letter reports our experimental results on magnetic-field-induced aftereffects in solution derived Bi4Fe2TiO12 film, in which e' decreases as much as 600 times after treated in a 5T magnetic field as that of the pristine one. The phenomena are explained ... More
An Optical and X-ray Examination of Two Radio Supernova Remnant Candidates in 30 DoradusJul 22 2004The giant HII region 30 Doradus is known for its violent internal motions and bright diffuse X-ray emission, suggesting the existence of supernova remnants (SNRs), but no nonthermal radio emission has been detected. Recently, Lazendic et al. compared ... More
Magnetodielectric effect of Bi6Fe2Ti3O18 film under an ultra-low magnetic fieldFeb 20 2006Feb 21 2006Good quality and fine grain Bi6Fe2Ti3O18 magnetic ferroelectric films with single-phase layered perovskite structure have been successfully prepared via metal organic decomposition (MOD) method. Results of low-temperature magnetocapacitance measurements ... More
Diffuse X-ray Emission within Wolf-Rayet NebulaeNov 03 2015We discuss our most recent findings on the diffuse X-ray emission from Wolf-Rayet (WR) nebulae. The best-quality X-ray observations of these objects are those performed by XMM-Newton and Chandra towards S308, NGC2359, and NGC6888. Even though these three ... More
Finite Size Scaling of the Higgs-Yukawa Model near the Gaussian Fixed PointNov 02 2016We study the scaling properties of Higgs-Yukawa models. Using the technique of Finite-Size Scaling, we are able to derive scaling functions that describe the observables of the model in the vicinity of a Gaussian fixed point. A feasibility study of our ... More
Two Ring Nebulae around Blue Supergiants in the Large Magellanic CloudApr 30 1997Ring nebulae are often found around massive stars such as Wolf-Rayet stars, OB and Of stars and Luminous Blue Variables (LBVs). In this paper we report on two ring nebulae around blue supergiants in the Large Magellanic Cloud. The star Sk-69 279 is classified ... More
A lattice study of a chirally invariant Higgs-Yukawa model including a higher dimensional $Φ^6$-termJan 22 2015We discuss the non-thermal phase structure of a chirally invariant Higgs-Yukawa model on the lattice in the presence of a higher dimensional $\Phi^6$-term. For the exploration of the phase diagram we use analytical, lattice perturbative calculations of ... More
On the NP-completeness of Finding an Optimal Strategy in Games with Common PayoffsMar 27 2001Consider a very simple class of (finite) games: after an initial move by nature, each player makes one move. Moreover, the players have common interests: at each node, all the players get the same payoff. We show that the problem of determining whether ... More
Field-Induced Resistive Switching in Metal-Oxide InterfacesFeb 27 2004We investigate the polarity-dependent field-induced resistive switching phenomenon driven by electric pulses in perovskite oxides. Our data show that the switching is a common occurrence restricted to an interfacial layer between a deposited metal electrode ... More
Why is the superconducting Tc so high in rare-earth-doped CaFe2As2?Aug 30 2013Sep 06 2013In rare-earth doped single crystalline CaFe2As2, the mysterious small volume fraction which superconducts up to 49 K, much higher than the bulk Tc ~ 30s K, has prompted a long search for a hidden variable that could enhance the Tc by more than 30% in ... More
Search for exotic short-range interactions using paramagnetic insulatorsApr 02 2015May 26 2015We describe a proposed experimental search for exotic spin-coupled interactions using a solid-state paramagnetic insulator. The experiment is sensitive to the net magnetization induced by the exotic interaction between the unpaired insulator electrons ... More
Unconventional Superconductivity and Electron Correlations in Cobalt Oxyhydrate Na$_{0.35}$CoO$_{2}$$\cdot y$H$_{2}$OJul 06 2003We report a precise $^{59}$Co nuclear quadrupolar resonance (NQR) measurement on the recently discovered cobalt oxyhydrate Na$_{0.35}$CoO$_{2}$$\cdot y$H$_{2}$O superconductor from $T$=40 K down to 0.2 K. We find that in the normal state the spin-lattice ... More
X-ray Emission from Wind Blown Bubbles. III. ASCA SIS Observations of NGC6888Jul 17 2005We present ASCA SIS observations of the wind-blown bubble NGC6888. Owing to the higher sensitivity of the SIS for higher energy photons compared to the ROSAT PSPC, we are able to detect a T ~ 8x10^6 K plasma component in addition to the T ~ 1.3x10^6 K ... More
Spectral Analysis of Mid-IR Excesses of White DwarfsFeb 02 2011In our Spitzer 24 \mu m survey of hot white dwarfs (WDs) and archival Spitzer study of pre-WDs, i.e., central stars of planetary nebulae (CSPNs), we found mid-IR excesses for -15 WDs/pre-WDs. These mid-IR excesses are indicative of the presence of circumstellar ... More
On the diffuse X-ray emission from the Wolf-Rayet Bubble NGC 2359Oct 08 2014A recent XMM-Newton observation (Zhekov 2014) has revealed diffuse X-ray emission inside the nebula NGC 2359 around the Wolf-Rayet star WR 7. Taking advantage of an improved point-source rejection and background subtraction, and a detailed comparison ... More
Sensitivity of Proposed Search for Axion-induced Magnetic Field using Optically Pumped MagnetometersFeb 05 2018We investigate a search for the oscillating current induced by axion dark matter in an external magnetic field using optically pumped magnetometers (OPMs). This experiment is based upon the LC circuit axion detection concept of Sikivie, Sullivan, and ... More
Bok Globules in the LMCFeb 10 1999We report the discovery of small, isolated dust clouds in the Large Magellanic Cloud, which are excellent candidates for counterparts to the Bok globules observed in the Galaxy. We detect these small clouds silhoutted against diffuse H-alpha emission, ... More
Superfluid response in monolayer high-Tc cupratesApr 02 2003We have studied the doping dependence of the in-plane and out-of-plane superfluid density, \rho^s(0), of two monolayer high-Tc superconductors, HgBa_2CuO_{4+\delta} and La_{2-x}Sr_xCuO_4, using the low frequency ac-susceptibility and the muon spin relaxation ... More
c-Axis Superfluid Response and Pseudogap in High-Tc SuperconductorsNov 09 1999To gain insight into the out-of-plane electrodynamics of high-$T_c$ superconduct ors we have measured the absolute values and temperature dependence of the c-a xis magnetic penetration depth $\lambda_c(T)$ for two typical single layer high -$T_c$ cuprates, ... More
Chandra Reveals the X-ray Glint in the Cat's EyeJan 25 2001We have obtained Chandra ACIS-S observations of NGC 6543, the Cat's Eye Nebula. The X-ray emission from NGC 6543 is clearly resolved into a point source at the central star and diffuse emission confined within the central elliptical shell and two extensions ... More
Supernova Remnants in the Large Magellanic Clouds IX: Multiwavelength Analysis of the Physical Structure of N49Aug 10 2007We present a multiwavelength analysis of the supernova remnant N49 in the Large Magellanic Cloud. Using high-resolution Hubble Space Telescope WFPC2 images of H-alpha, [S II] and [O III] emission, we study the morphology of the remnant and calculate the ... More
Hot Gas in the Circumstellar Bubble S308Sep 05 2003S308 is a circumstellar bubble blown by the WN4 star HD50896. It is one of the only two single-star bubbles that show detectable diffuse X-ray emission. We have obtained XMM-Newton EPIC observations of the northwest quadrant of S308. The diffuse X-ray ... More
Detection of an X-ray Pulsar Wind Nebula and Tail in SNR N157BMay 18 2001We report Chandra X-ray observations of the supernova remnant N157B in the Large Magellanic Cloud, which are presented together with an archival HST optical image and a radio continuum map for comparison. This remnant contains the recently discovered ... More
Sensitivity of Proposed Search for Axion-induced Magnetic Field using Optically Pumped MagnetometersFeb 05 2018Feb 07 2018We investigate a search for the oscillating current induced by axion dark matter in an external magnetic field using optically pumped magnetometers (OPMs). This experiment is based upon the LC circuit axion detection concept of Sikivie, Sullivan, and ... More
XMM-Newton RGS observations of the Cat's Eye NebulaOct 28 2014We present an analysis of XMM-Newton Reflection Grating Spectrometer (RGS) observations of the planetary nebula (PN) NGC 6543, rendering it the second PN with high resolution X-ray spectroscopic observations besides BD+30 3639. The observations consist ... More
X-ray Emission from the Wolf-Rayet Bubble NGC 6888. I. Chandra ACIS-S ObservationsOct 10 2013Dec 03 2013We analyze Chandra observations of the Wolf-Rayet (WR) bubble NGC 6888. This WR bubble presents similar spectral and morphological X-ray characteristics to those of S 308, the only other WR bubble also showing X-ray emission. The observed spectrum is ... More
The Unusual Superconducting State at 49 K in Electron-Doped CaFe2As2 at AmbientJun 10 2011Jun 29 2011We report the detection of unusual superconductivity up to 49 K in single crystalline CaFe2As2 via electron-doping by partial replacement of Ca by rare-earth. The superconducting transition observed suggests the possible existence of two phases: one starting ... More
Neutron scattering study of novel magnetic order in Na0.5CoO2Aug 05 2005We report polarized and unpolarized neutron scattering measurements of the magnetic order in single crystals of Na0.5CoO2. Our data indicate that below T_N=88 K the spins form a novel antiferromagnetic pattern within the CoO2 planes, consisting of alternating ... More
Electromagnetic Field Tensor and Lorentz Force as Consequence of the Geometry of Minkowskian SpacetimeMay 19 1999May 20 1999We show that the electromagnetic field tensor and the Lorentz Force are both a natural consequence of the geometric structure of Minkowskian space, being related to infinitesimal boosts and rotations in spacetime. The longstanding issue about the apparent ... More
Multilayer microwave integrated quantum circuits for scalable quantum computingSep 03 2015Sep 11 2015As experimental quantum information processing (QIP) rapidly advances, an emerging challenge is to design a scalable architecture that combines various quantum elements into a complex device without compromising their performance. In particular, superconducting ... More
Hard X-ray Emission Associated with White DwarfsJan 14 2003We have used the WGACAT to search for hard X-ray sources associated with white dwarfs (WDs) from the catalog of McCook & Sion (1999). We find 17 X-ray sources coincident with WDs showing significant hard X-ray emission at energies >0.5 keV. Twelve of ... More
The effect of electron holes on cyclotron maser emission driven by horseshoe distributionsNov 07 2016This Brief Communication presents a quantitative investigation for the effect of electron holes on electron-cyclotron maser (ECM) driven by horseshoe distributions. The investigation is based on an integrated distribution function for the horseshoe distributions ... More
Populating Dark Matter Haloes with Galaxies: Comparing the 2dFGRS with Mock Galaxy Redshift SurveysMar 24 2003Feb 20 2004In two recent papers, we developed a powerful technique to link the distribution of galaxies to that of dark matter haloes by considering halo occupation numbers as function of galaxy luminosity and type. In this paper we use these distribution functions ... More
High-pressure study of superconducting and non-superconducting single crystals of the same nominal composition Rb0.8Fe2Se2Oct 27 2011Two single crystalline samples with the same nominal composition of Rb0.8Fe2Se2 prepared via slightly different precursor routes under the same thermal processing conditions were investigated at ambient and high pressures. One sample was found superconducting ... More
A Neutral Hydrogen Survey of the Large Magellanic Cloud: Aperture Synthesis and Multibeam Data CombinedJun 10 2005Using a Fourier-plane technique, we have merged HI ATCA and Parkes data sets providing an accurate set of images of the LMC sensitive to structure on scales of 15 pc (for an LMC distance of 55 kpc) upwards. The spatial dynamic range (2.8 orders of magnitude), ... More
Evidence for multiple gaps in specific heat of LiFeAs crystalsApr 06 2010The zero-field specific heat of LiFeAs was measured on several single crystals selected from a bulk sample. A sharp Delta Cp/Tc anomaly of approximately 20 mJ/(mole x K^2) was observed. The value appears to be between those of SmFeAs(O0.9F0.1) and (Ba0.6K0.4)Fe2As2, ... More
Searching for Stable Na-ordered Phases in Single Crystal Samples of gamma-NaxCoO2Aug 02 2007We report on the preparation and characterization of single crystal gamma phase NaxCoO2 with 0.25 < x < 0.84 using a non-aqueous electrochemical chronoamperemetry technique. By carefully mapping the overpotential versus x (for x < 0.84), we find six distinct ... More
A Possible Crypto-Superconducting Structure in a Superconducting FerromagnetFeb 14 2000We have measured the dc and ac electrical and magnetic properties in various magnetic fields of the recently reported superconducting ferromagnet RuSr2GdCu2O8. Our reversible magnetization measurements demonstrate the absence of a bulk Meissner state ... More
Raman Phonons and Ageing-Related Surface Disorder in NaxCoO2Aug 04 2003Oct 16 2003The polarized Raman spectra from ab and ac surfaces of single crystal NaxCoO2 (x~0.7), parent compound of recently discovered superconductor NaxCoO2.yH2O, are reported and discussed. The crystals were hexagon platelets of typical size 3x3x0.1 mm. Three ... More
Experimental realization of an optical antenna for collecting 99% of photons from a quantum emitterJun 03 2014We present the fabrication and characterization of an optical antenna that converts the dipolar radiation of a quantum emitter to a directional beam with 99% efficiency. Aside from its implications for efficient detection of nanoscopic emitters, this ... More
X-ray emission from the Wolf-Rayet bubble NGC 6888. II. XMM-Newton EPIC observationsDec 03 2015We present deep XMM-Newton EPIC observations of the Wolf-Rayet (WR) bubble NGC6888 around the star WR136. The complete X-ray mapping of the nebula confirms the distribution of the hot gas in three maxima spatially associated with the caps and northwest ... More
Lattice study of the Higgs-Yukawa model in and beyond the Standard ModelOct 29 2015Nov 02 2015We derive finite-size scaling formulae for four-dimensional Higgs-Yukawa models near the Gaussian fixed point. These formulae will play an essential role in future, detailed investigation of such models. In particular, they can be used to determine the ... More
Metastable giant moments in Gd-implanted GaN, Si, and sapphireMar 28 2011We report on Gd ion implantation and magnetic characterization of GaN films on sapphire substrates and of bare sapphire and Si substrates to shed light on the mechanism underlying the induced magnetism upon Gd ion implantation. For all three hosts, giant ... More
Micromachined integrated quantum circuit containing a superconducting qubitNov 07 2016We present a device demonstrating a lithographically patterned transmon integrated with a micromachined cavity resonator. Our two-cavity, one-qubit device is a multilayer microwave integrated quantum circuit (MMIQC), comprising a basic unit capable of ... More
Staging model of the ordered stacking of vacancy layers and phase separation in the layered NaCoO(x > 0.71) single crystalsJan 06 2009Jul 13 2009Phase diagram of Na$_x$CoO$_2$ (x $\gtrsim$ 0.71) has been reinvestigated using electrochemically fine tuned single crystals. Both phase separation and staging phenomena as a result of sodium multi-vacancy cluster ordering have been found. Phase separation ... More
Phase structure and Higgs boson mass in a Higgs-Yukawa model with a dimension-6 operatorJan 01 2015We investigate the impact of a $\lambda_6 \varphi^6$ term included in a chirally invariant lattice Higgs-Yukawa model. Such a term could emerge from BSM physics at some larger energy scale. We map out the phase structure of the Higgs-Yukawa model with ... More
Magnetic field-induced spontaneous polarization reversal in multiferroic Mn$_{0.85}$Co$_{0.15}$WO$_4$Feb 04 2014The magnetic and ferroelectric properties of the multiferroic system Mn$_{1-x}$Co$_x$WO$_4$ (x=0.135, 0.15, and 0.17) are studied in magnetic fields $H_c$ oriented along the monoclinic $c$-axis. Mn$_{0.85}$Co$_{0.15}$WO$_4$, which is right at the phase ... More
The complex multiferroic phase diagram of Mn$_{1-x}$Co$_x$WO$_4$Jun 28 2012The complete magnetic and multiferroic phase diagram of Mn$_{1-x}$Co$_{x}$WO$_4$ single crystals is investigated by means of magnetic, heat capacity, and polarization experiments. We show that the ferroelectric polarization $\overrightarrow{P}$ in the ... More
Absence of a Bulk Meissner State in RuSr2GdCu2O8Oct 05 1999Dec 23 1999We have systematically investigated the magnetic, electrical, and structural properties of RuSr2GdCu2O8, in which a long-range ferromagnetic order and superconductivity have been previously reported to coexist. Based on the reversible magnetization results, ... More
Robust Ferroelectric State in Multiferroic Mn$_{1-x}$Zn$_x$WO$_4$Nov 30 2010Jan 11 2011We report the remarkably robust ferroelectric state in the multiferroic compound Mn$_{1-x}$Zn$_x$WO$_4$. The substitution of the magnetic Mn$^{2+}$ with nonmagnetic Zn$^{2+}$ reduces the magnetic exchange and provides control of the various magnetic and ... More
Searching for a preferred direction with Union2.1 dataOct 19 2013A cosmological preferred direction was reported from the type Ia supernovae (SNe Ia) data in recent years. We use the Union2.1 data to give a simple classification of such studies for the first time. Because the maximum anisotropic direction is independent ... More
Magnetic and multiferroic phases of single-crystalline Mn$_{0.85}$Co$_{0.15}$WO$_4$Nov 30 2010The magnetic and multiferroic phase diagram of Mn$_{0.85}$Co$_{0.15}$WO$_4$ single crystals is investigated by means of magnetic, heat capacity, dielectric, polarization, and neutron scattering experiments. Three magnetic phase transitions are detected ... More
Incommensurate magnetic structure in the orthorhombic perovskite ErMnO_3Jul 03 2007Aug 02 2007By combining dielectric, specific heat, and magnetization measurements and high-resolution neutron powder diffraction, we have investigated the thermodynamic and magnetic/structural properties of the metastable orthorhombic perovskite ErMnO_3 prepared ... More
Great Expectations. Part I: On the Customizability of Generalized Expected UtilityNov 20 2003We propose a generalization of expected utility that we call generalized EU (GEU), where a decision maker's beliefs are represented by plausibility measures, and the decision maker's tastes are represented by general (i.e.,not necessarily real-valued) ... More
A decision-theoretic approach to reliable message deliverySep 21 1999We argue that the tools of decision theory need to be taken more seriously in the specification and analysis of systems. We illustrate this by considering a simple problem involving reliable communication, showing how considerations of utility and probability ... More
Feedback from Massive YSOs and Massive StarsDec 07 2010Massive stars are powerful sources of radiation, stellar winds, and supernova explosions. The radiative and mechanical energies injected by massive stars into the interstellar medium (ISM) profoundly alter the structure and evolution of the ISM, which ... More
An Intriguing X-ray Arc Surrounding the X-ray Source RX J053335-6854.9 toward the Large Magellanic CloudOct 10 2003ROSAT observations of the Large Magellanic Cloud (LMC) have revealed a large diffuse X-ray arc around the point source RX J053335-6854.9. The relative locations of the diffuse and point sources suggest that they might originate from a common supernova ... More
Discovery of Extreme Carbon Stars in the Large Magellanic CloudSep 30 2008Using Spitzer IRAC and MIPS observations of the Large Magellanic Cloud, we have identified 13 objects that have extremely red mid-IR colors. Follow-up Spitzer IRS observations of seven of these sources reveal varying amounts of SiC and C2H2 absorption ... More
Chandra Observation of the Magellanic Cloud Supernova Remnant 0454-672 in N9Nov 21 2005A Chandra observation has defined the extent of the SNR B 0454-692 in the LMC H II region N9. The remnant has dimension 2.3" x 3.6" and is elongated in the NS direction. The brightest emission comes from a NS central ridge which includes three bright ... More
Observation of ferromagnetic resonance in strontium ruthenate (SrRuO3)Dec 03 2008We report the observation of ferromagnetic resonance (FMR) in SrRuO3 using the time-resolved magneto-optical Kerr effect. The FMR oscillations in the time-domain appear in response to a sudden, optically induced change in the direction of easy-axis anistropy. ... More
Indirect excitons in a potential energy landscape created by a perforated electrodeFeb 08 2016We report on the principle and realization of an excitonic device: a ramp that directs the transport of indirect excitons down a potential energy gradient created by a perforated electrode at constant voltage. The device provides an experimental proof ... More
Structure Based Extended Resolution for Constraint ProgrammingJun 19 2013Nogood learning is a powerful approach to reducing search in Constraint Programming (CP) solvers. The current state of the art, called Lazy Clause Generation (LCG), uses resolution to derive nogoods expressing the reasons for each search failure. Such ... More
Probing the role of single defects on the thermodynamics of electric-field induced phase transitionsFeb 04 2008The kinetics and thermodynamics of first order transitions is universally controlled by defects that act as nucleation sites and pinning centers. Here we demonstrate that defect-domain interactions during polarization reversal processes in ferroelectric ... More
Supernova Remnants in the Magellanic Clouds. IV. X-Ray Emission from the Largest SNR in the LMCJun 11 2004We present the first X-ray detection of SNR 0450-70.9 the largest known supernova remnant (SNR) in the Large Magellanic Cloud. To study the physical conditions of this SNR, we have obtained XMM-Newton X-ray observations, optical images and high-dispersion ... More
Hot Interstellar Gas and Stellar Energy Feedback in the Antennae GalaxiesJan 21 2004We have analyzed Chandra archival observations of the Antennae galaxies to study the distribution and physical properties of its hot interstellar gas. Eleven distinct diffuse X-ray emission regions are selected according to their underlying interstellar ... More
Supernova Remnants in the Magellanic Clouds. V. The Complex Interior Structure of the N206 SNRApr 27 2005The N206 supernova remnant (SNR) in the Large Magellanic Cloud (LMC) has long been considered a prototypical "mixed morphology" SNR. Recent observations, however, have added a new twist to this familiar plot: an elongated, radially-oriented radio feature ... More
Demonstration of superconducting micromachined cavitiesSep 03 2015Sep 11 2015Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics (cQED). Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether ... More
Ultrafast modelocked nonlinear micro-cavity laserApr 22 2014Ultrashort pulsed lasers, operating through the phenomenon of mode-locking, have played a significant role in many facets of our society for 50 years, for example in the way we exchange information, measure and diagnose diseases, process materials and ... More
Evidence for effective thermal boundary resistance from magnon/phonon disequilibriumJan 25 2010We use the time-resolved magneto-optical Kerr effect (TRMOKE) to measure the local temperature and heat flow dynamics in ferromagnetic SrRuO3 thin films. After heating by a pump pulse, the film temperature decays exponentially, indicating that the heat ... More
Magnetic switching and phase competition in the multiferroic antiferromagnet $\rm Mn_{1-x}Fe_xWO_4$Oct 31 2008Elastic neutron scattering is used to study the spin correlations in the multiferroic $\rm Mn_{1-x}Fe_{x}WO_4$ with $x=0.035, 0.05$ and 0.10. The noncollinear, incommensurate (ICM) magnetic structure associated with the ferroelectric (FE) phase in pure ... More
An X-ray investigation of the NGC346 field in the SMC (1) : the LBV HD5980 and the NGC346 clusterAug 15 2002We present results from a Chandra observation of the NGC346 cluster. This cluster contains numerous massive stars and is responsible for the ionization of N66, the most luminous HII region and the largest star formation region in the SMC. In this first ... More
The Synthesis and Characterization of LiFeAs and NaFeAsFeb 04 2009The newest homologous series of superconducting As-pnictides, LiFeAs (Li111) and NaFeAs (Na111) have been synthesized and investigated. Both crystallize with the layered tetragonal anti-PbFCl-type structure in P4/nmm space group. Polycrystalline samples ... More
Transport of Indirect Excitons in a Potential Energy GradientMar 28 2012May 31 2012We realized a potential energy gradient - a ramp - for indirect excitons using a shaped electrode at constant voltage. We studied transport of indirect excitons along the ramp and observed that the exciton transport distance increases with increasing ... More
Nonmagnetic impurity perturbation to the quasi-two-dimensional quantum helimagnet LiCu2O2Jun 28 2010A complete phase diagram of Zn substituted quantum quasi-two-dimensional helimagnet LiCu2O2 has been presented. Helical ordering transition temperature (T_h) of the original LiCu2O2 follows finite size scaling for less than ~ 5.5% Zn substitution, which ... More