Design Physical Property Measurement System Research Articles

Magnetic Analysis of MgFe Hydrotalcites as Powder and Dispersed in Thin Films within a Keratin Matrix.

Hydrotalcites (HTlcs) are a class of nanostructured layered materials that may be employed in a variety of applications, from green to bio technologies. In this paper, we report an investigation on HTlcs made of Mg and Fe, recently employed to improve the growth in vitro of osteoblasts within a keratin sponge. We carried out an analysis of powder materials and of HTlcs dispersed in keratin and spin-coated on a Si/SiO2 substrate at different temperatures. A magnetic study of the powders was carried out with a Quantum Design Physical Property Measurement System equipped with a Vibrating Sample Magnetometer. The data gathered prove that these HTlcs are fully paramagnetic, and keratin showed a very small magnetic response. Optical and Atomic Force Microscopy analyses of the thin films provide a detailed picture of clusters randomly dispersed in the films with various dimensions. The magnetic properties of these films were characterized using the Nano Magneto Optical Kerr Effect (NanoMOKE) down to 7.5 K. The data collected show that the local magnetic properties can be mapped with a micrometric resolution distinguishing HTlc regions from keratin ones. This approach opens new perspectives in the characterization of these composite materials.

Heat capacity of cytisine – the drug for smoking cessation

The characterization of cytisine (CYT) and its blends with poly(lactic acid) was performed using thermal analysis, elemental analysis, infrared spectroscopy, and powder X-ray diffractometry. The heat capacities, total enthalpy, and phase transitions of CYT were established from 1.8 to 448.15 K (−271.35 – 175 °C) by advanced thermal analysis. Data were obtained using a Quantum Design Physical Property Measurement System (PPMS) and a differential scanning calorimetry (DSC). The low-temperature heat capacity of the crystalline CYT in the range of 1.8 to 300 K (−271.35 – 26.86 °C) was measured by PPMS and fitted to a theoretical model in the low temperature region below 11 K (−262.15 °C), to orthogonal polynomials in the middle range 5 K <T < 60 K (−268.15 °C < t < −213.15 °C) and to the Debye and Einstein functions in the high range of temperature above 60 K (−213.15 °C). The liquid heat capacity was calculated based on the approximated linear regression data above the molten state of the experimental heat capacity of CYT obtained by the standard DSC measurements, and it was expressed as Cpliquid = 0.0838T + 346.78 J·K−1·mol−1. The calculated heat capacity in the solid state was extended to a higher temperature and was used, together with liquid heat capacity, as the reference baselines for the advanced thermal analysis of CYT. The PPMS and DSC/TMDSC methods are complementary methods for thermal analysis of cytisine. The PPMS method allowed determination of the equilibrium heat capacity in the solid state, which together with the equilibrium heat capacity in the liquid state allowed to analyze of the experimental apparent heat capacity of cytisine obtained based on DSC. The melting temperature and the total heat of fusion of crystalline material were established as 431.8 K (158.65 °C) and 26.5 kJ·mol−1, respectively. The solid and liquid heat capacities and transition parameters of CYT were applied to calculate total enthalpies for fully amorphous and crystalline states. Analyses of DSC and X-ray confirmed the presence of the solid-solid transition linking with not so far described a polymorphism phenomenon of CYT. Based on the thermogravimetric analysis the temperature of degradation of CYT was determined as 460.5 K (187.35 °C). Also, a preliminary thermal analysis of the blends of cytisine and poly(lactic acid) as a new candidate for drug delivery system was presented.

A Smart Molecule Showing Spin Crossover Responsive Aggregation-Induced Emission

A Smart Molecule Showing Spin Crossover Responsive Aggregation-Induced Emission

Application of advanced thermal analysis for characterization of crystalline and amorphous phases of carvedilol

The thermal behaviour of crystalline and amorphous carvedilol (CAR) phases was studied by advanced thermal analysis using Quantum Design Physical Property Measurement System and Differential Scanning Calorimetry. Theoretical functions describing crystalline carvedilol heat capacity at low temperatures and the Debye-Einstein function for high temperatures were obtained. Based on the experimental heat capacity values, solid and liquid baselines were established, and the state functions (H, S, G) for solid and liquid states were calculated. A comprehensive characterization of melting and glass transition processes was obtained. CAR is easily amorphizable by cooling the liquid. The residual entropy, which quantifies the extent of frozen-in disorder in the amorphous solid, for glassy CAR was estimated as 51 J·mol–1·K–1. The Kauzmann temperature (TK) was estimated based on enthalpy and entropy. Molecular motions in the amorphous phase were also studied. The activation energy for structural relaxation (Ea = 539 kJ·mol–1) and fragility parameter (m = 91) were obtained from the non-isothermal physical ageing. The isothermal physical ageing kinetics of amorphous CAR was studied by applying Kohlrausch-Williams-Watts (KWW) model. The mean molecular relaxation time constant (τKWW = 117 min) and relaxation constant (βKWW = 0.33) were obtained. CAR was classified as a fragile glass-former. Furthermore, τKWW constant for samples aged at 303.15 K is very low, thus, the physical ageing will occur during the short- and long-term storage of amorphous CAR, potentially changing its physicochemical properties during the ageing process. However, the results of molecular mobility studies (high molecular motions) show that the relationship between molecular motions in a glassy solid and its tendency to crystallization does not seem to follow an expected pattern, i.e., no crystallization occurred by thermal treatment of glassy, supercooled liquid and liquid phases of CAR as one would expect. Modern calorimetry and quantitative thermal analysis provided the fundamental kinetic and thermodynamic information about the crystalline and amorphous states of CAR.

Heat capacity, entropy, formation energy and spin-fluctuation behavior of U3Si5 from 2.4 to 397.4 K

• Heat capacity data of U3Si5 were obtained using a Quantum Design Physical Properties Measurement System (PPMS) from 2.4 to 397.4 K. • An upturn characteristic of spin-fluctuations in Cp/T (T) was observed below 10 K. • The Gibbs free energy of formation of U3Si5 from the elements was determined to be –45.2 ± 9.0 kJ•mol−1•atom−1. U-Si intermetallic compounds are of considerable interest for their applications as accident-tolerant nuclear fuels. Here we present low-temperature heat capacity (LTHC) measurements of one of the U-Si phases, U 3 Si 5 , using a Quantum Design Physical Properties Measurement System (PPMS) from 2.4 to 397.4 K. We observed an upturn in C p /T (T) below 10 K and have attributed this behavior to potential spin-fluctuations (SF) with an SF temperature (T sf ) of 27 K. An enhancement of LTHC was also observed, as manifested by a large electronic heat capacity coefficient (γ el ) of 342.9 mJ/mol•K 2 . From the heat capacity data, the following thermodynamic parameters were determined: the characteristic Debye temperature ( θ D ) over the temperature range 30 – 397 K is 177 ± 2 K, and the standard entropy ( Δ 0 298 . 15 S ∘ ) is 283.3 ± 5.7 J•mol −1 •K −1 (equivalent to 35.4 ± 0.7 J•mol −1 •atom −1 •K −1 ). Combined with our previously measured formation enthalpy ( Δ f H e l ∘ ) of U 3 Si 5 , the Gibbs free energy of formation of U 3 Si 5 from the elements ( Δ f G e l ∘ ) was determined to be –45.2 ± 9.0 kJ•mol −1 •atom −1 .

Impact of particle size on the magnetic properties of highly crystalline Yb3+ substituted Ni–Zn nanoferrites

Yb-substituted Ni0.5Zn0.5YbxFe2−xO4 (0 ≤ x ≤ 0.20 in the step of 0.04) ferrites have been synthesized using sol–gel auto combustion method. The structural characterization of the compositions has been performed by X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), quantum design physical properties measurement system (PPMS) that ensured the formation of single phase cubic spinel structure. Crystallite and average grain size are calculated and found to decrease with increasing Yb3+ contents. Saturation magnetization (Ms) and Bohr magnetic moment (µB) decrease while the coercivity increases with the increase in Yb3+ contents and successfully explained by the Neel’s collinear two sub-lattice model and critical size effect, respectively. Critical particle size has been estimated at 6.4 nm from the DXRD vs. Ms, Hc plot, the transition point between single domain regime (below the critical size) and multi-domain regime (beyond the critical size). Curie temperature (Tc) reduces due to the weakening of A–O–B super exchange interaction and redistribution of cations, confirmed by the M–T graph. The compositions retain ferromagnetic ordered structured below Tc and above Tc, it becomes paramagnetic, making them plausible candidates for high temperature magnetic device applications. The relative quality factor (RQF) peak is obtained at a very high frequency (≥ 108 MHz), indicating the compositions could also be applicable for high frequency magnetic device applications.

Impact of Sn4+ substitution in Mg–Zn ferrites: Deciphering the structural, morphological, dielectric, electrical and magnetic properties

From the viewpoint of enormous applications and research, ferrite materials have already been achieved the status of one of the important branches of materials science. In this report, we have tuned the physical properties of Mg–Zn ferrites by Sn substitution investigated using X-ray diffraction, field emission scanning electron microscopy (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, electrical and dielectric properties and quantum design physical properties measurement system. The Mg0·5Zn0.5SnxFe2-xO4 (0 ≤ x ≤ 0.10) samples have been synthesized by the conventional ceramic technique. The studied ferrites exhibits the single-phase up to x = 0.08 where an increase in lattice constant was observed. The FESEM images revealed the microstructure and the energy dispersive spectroscopy (EDS) confirms the absence of any unwanted elements. The increase (decrease) in bulk density (porosity) was associated with the variation of average grain size. FTIR spectra confirmed the formation of spinel structure. The dielectric polarization or conduction mechanism in these materials is due to the hopping of charge carriers at the octahedral sites. The common dielectric behavior of studied compositions is also observed. The substitution of Sn ions leads to enhanced dielectric constant and ac conductivity due to increased hopping of charge carriers. Complex impedance spectroscopy study revealed the non-Debye type of relaxation process within the studied compositions with a dominant contribution from grain boundary resistance. The dynamic magnetic hysteresis loops are measured to obtain the magnetic parameters. The low values of coercivity revealed the soft magnetic nature of the studied compositions. The obtained saturation magnetization (Ms) for Mg–Zn ferrite (x = 0.00) is comparable with the prior result. Non-linear decrease of Ms (62-44 emu/g) due to Sn substitution is explained based on the variation of magnetic moments over A- and B-sites. The squareness ratio (Mr/Ms) revealed that the magneto-statical interaction is present within the synthesized samples. The constant value of initial permeability (μʹ) over a wide range of frequencies revealed the compositional stability and quality of the prepared ferrite. The variation of μʹ with Sn content is similar to that of Msvs Sn contents. Moreover, theoretical cation distribution and the effect of Sn substitution on the related parameters have also been studied. The studied parameters are compared with the reported results, where available.

Magnetoresistance Behavior of Cryogenic Temperature Sensors Based on Single-Walled Carbon Nanotubes

We report on the experimental investigation of the magnetoresistance behavior of cryogenic temperature sensors based on single-walled carbon nanotubes (SWCNTs) as a function of temperature and magnetic flux density; one sensor was based on layers/networks of unsorted SWCNT of various chiralities, and one on SWCNTs layers of (7,6) chirality. SWCNT-based sensors were fabricated according to a straightforward method, and the electrical properties were measured from room temperature down to 2 K using a Quantum Design Physical Property Measurement System (PPMS). The two sensors present different magneto-transport behavior, with the magnetoresistance dependence on the magnetic field being a sum of two terms with positive and negative contributions respectively. The expression for magnetoresistance is derived together with its experimentally determined coefficients. For both sensors, the electrical resistance dependence on temperature below the 80 K mark is explained by Mott's law of variable-range hopping. The experimentally obtained hopping dimension d values of 2.67 for the system comprised of purified (7,6) chirality SWCNTs and 2.97 for the system comprised of unsorted SWCNTs are in good agreement with the theory. As a second step, the magnetic field was kept constant and at different values, while the temperature was scanned over the investigated domain.

Crystal structure and thermodynamic properties of the coordination compound calcium D-gluconate Ca[D-C6H11O7]2(s)

The coordination compound calcium D-gluconate, Ca[D-C6H11O7]2(s), was synthesized and characterized by chemical analysis, elemental analysis, and X-ray crystallography. Single crystal X-ray diffraction technique revealed that the compound was formed by two D-gluconate anions and one calcium (II) cation. And the D-gluconate anion had a curved chain configuration with an intramolecular bond. The compound exhibited an outstanding chelate property of D-gluconate anions to calcium (II) cations, and the calcium (II) cation was eight-coordinated and chelated by four D-gluconate anions. The lattice potential energy and ionic volume of the anion were calculated to be 1434.05 kJ⋅mol−1 and 0.4211 nm3 from crystallographic data. In accordance with famous Hess law, a reasonable thermochemical cycle was designed and the standard molar enthalpy of formation of Ca[D-C6H11O7]2(s) was calculated as ΔsHm[Ca[D-C6H11O7]2, s] = -(3545.19 ± 1.07) kJ⋅mol−1 by use of an isoperibol solution-reaction calorimeter. Furthermore, molar heat capacities of the compound were measured using a Quantum Design Physical Properties Measurement System (PPMS) with specific heat option within the temperature range from (1.9–300) K. The heat capacities of the compound increased with the temperature and no thermal anomaly was found in the whole temperature region. The experimental data was fitted to a function of the absolute temperature T with a series of theoretical and empirical models for the proper temperature ranges. The values of standard thermodynamic function, Cp,mo/J⋅K−1⋅mol−1, Δ0THmo/kJ⋅mol−1, Δ0TSmo/J⋅K−1⋅mol−1, and ΔoTGmo/T/J⋅K−1⋅mol−1 (=Δ0TSmo-Δ0THmo/T) from T = (0–300) K was calculated based on the fitting results. The standard molar heat capacity, entropy and enthalpy of the compound at T = 298.15 K and 0.1 MPa was determined to be Cp,mo= (493.20 ± 2.70) J·K−1 mol−1, Hmo= (75934 ± 805) J·mol−1, Smo= (471.55 ± 2.78) J·K−1 mol−1, and Gmo/T = - (64658 ± 808) J·K−1⋅mol−1, respectively.

The surprising thermal properties of CM carbonaceous chondrites

AbstractMeasurements of the low‐temperature thermodynamic and physical properties of meteorites provide fundamental data for the study and understanding of asteroids and other small bodies. Of particular interest are the CM carbonaceous chondrites, which represent a class of primitive meteorites that record substantial chemical information concerning the evolution of volatile‐rich materials in the early solar system. Most CM chondrites are petrographic type 2 and contain anhydrous minerals such as olivine and pyroxene, along with abundant hydrous phyllosilicates contained in the meteorite matrix interspersed between the chondrules. Using a Quantum Design Physical Property Measurement System, we have measured the thermal conductivity, heat capacity, and thermal expansion of five CM2 carbonaceous chondrites (Murchison, Murray, Cold Bokkeveld, Northwest Africa 7309, Jbilet Winselwan) at low temperatures (5–300 K) which span the range of possible surface temperatures in the asteroid belt and outer solar system. The thermal expansion measurements show a substantial and unexpected decrease in CM2 volume as temperature increases from 210 to 240 K followed by a rapid increase in CM2 volume as temperature rises from 240 to 300 K. This transition has not been seen in anhydrous CV or CO carbonaceous chondrites. Thermal diffusivity and thermal inertia as a function of temperature are calculated from measurements of density, thermal conductivity, and heat capacity. Our thermal diffusivity results compare well with previous estimates for similar meteorites, where conductivity was derived from diffusivity measurements and modeled heat capacities; our new values are of higher precision and cover a wider range of temperatures.

Vibrational heat capacity of silver carp collagen

The study of the experimental and calculated heat capacity, Cp of fish collagen (silver carp) with contents of several additive components was presented. The experimental low-temperature heat capacity was measured in the temperature range of 1.85 to 302.8 K using a Quantum Design Physical Property Measurement System (PPMS) and the higher temperature Cp from 223.15 K to 382.15 K by Differential Scanning Calorimetry (DSC) method. For an interpretation of the experimental, low-temperature data, the vibrational heat capacity of the pure silver carp collagen was calculated based on the contribution of a sum of the vibrational heat capacity of 4248 amino acids. The vibrational heat capacity for each amino acids was taken from Advanced Thermal Analysis System (ATHAS) Data Bank for individual poly (amino acid) residues based on their group and skeletal vibrational spectra. Comparing of the experimental heat capacity of the collagen with additive components and the calculated vibrational heat capacity of the pure silver carp collagen shows that the differences range from around 10% at 100 K to 14% at 300 K temperature. Such thermal analysis can provide information about the contribution to Cp of unknown components or impurities in the investigated system.

Low-temperature heat capacities, standard molar enthalpies of formation and detonation performance of two CL-20 cocrystal energetic materials

Two cocrystals of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) with 2,4,6-trinitrotoluene (TNT) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) were prepared by a solvent/non-solvent (acetonitrile/distilled water) method at room temperature. The low-temperature heat capacities of CL-20∙TNT cocrystal and 2CL-20·HMX cocrystal were measured in the temperature range from 1.9 to 300 K using the heat capacity option of a Quantum Design Physical Property Measurement System (PPMS). By fitting the heat capacity data to a series of theoretical and empirical models, the thermodynamic functions were derived. In addition, the standard molar heat capacities, entropies and enthalpies of cocrystal samples at 298.15 K and 0.1 MPa were also obtained. The standard molar energies of combustion of CL-20, TNT, HMX, CL-20∙TNT cocrystal, and 2CL-20·HMX cocrystal were determined. From the combustion results, the standard molar enthalpies of combustion and formation for the compounds at T = 298.15 K were derived. The detonation velocity (D) and detonation pressure (P) were obtained by Kamlet-Jacobs equations. 2CL-20·HMX cocrystal shows superior detonation velocity and detonation pressure, which are higher than those of CL-20∙TNT cocrystal.

Quantum effects in graphitic materials: Colossal magnetoresistance, Andreev reflections, ferromagnetism, and granular superconductivity

Unlike the more common local conductance spectroscopy, nonlocal conductance can differentiate between nontopological zero-energy modes localized around inhomogeneities, and true Majorana edge modes in the topological phase. In particular, negative nonlocal conductance is dominated by the crossed Andreev reflection. Fundamentally, the effect reflects the system’s topology. In graphene, the Andreev reflection and the inter-band Klein tunneling couple electronlike and hole-like states through the action of either a superconducting pair potential or an electrostatic potential. We are here probing quantum phenomena in modified graphitic samples. Four-point contact transport measurements at cryogenic to room temperatures were conducted using a Quantum Design Physical Property Measurement System. The observed negative nonlocal differential conductance Gdiff probes the Andreev reflection at the walls of the superconducting grains coupled by Josephson effect through the semiconducting matrix. In addition, Gdiff shows the butterfly shape that is characteristic to resistive random-access memory devices. In a magnetic field, the Andreev reflection counters the effect of the otherwise lowered conduction. At low temperatures, the magnetoresistance shows irreversible yet strong giant oscillations that are known to be quantum in nature. In addition, we have found evidence for seemingly granular superconductivity. Thus, graphitic materials show potential for quantum electronics applications, including rectification and topological states.

Mechanical behavior, enhanced dc resistivity, energy band gap and high temperature magnetic properties of Y-substituted Mg–Zn ferrites

We report the synthesis of Y-substituted Mg–Zn [Mg0.5Zn0.5Y x Fe2−x O4 (0 ≤ x ≤ 0.05)] ferrites using conventional standard ceramic technique. The samples were characterized by x-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), FTIR spectroscopy, UV–Vis spectroscopy and quantum design physical properties measurement system (PPMS). XRD patterns confirm the single phase cubic spinel structure up to x = 0.03 and appearance of a secondary phase of YFeO3 for higher Y contents. FESEM images depict the distribution of grains and EDS spectra confirmed the absence of any unwanted element. Completion of solid state reaction and formation of spinel structure has been revealed from FTIR spectra. The FTIR data along with lattice constant, bulk density and porosity were further used to calculate the stiffness constant (C ij), elastic constant and Debye temperatures. Mechanical stability of all studied compositions is confirmed from C ij using Born stability conditions. Brittleness and isotropic nature are also confirmed using Poisson’s ratio and anisotropy constants, respectively. The enhancement of dc electrical resistivity (105Ω cm to 106Ω cm) with Y content is observed. The energy band gap (increased with Y contents) is found in good agreement with dc electrical resistivity. Ferrimagnetic to paramagnetic phase change has been observed from the field dependent high temperature magnetization curves. The magnetic moments and saturation magnetization were found to be decreased with increasing temperature. The Curie temperature (Tc) has been measured from temperature dependent magnetic moment (M-T) and initial permeability (μ′i-T) measurements and found to be in good agreement with each other. Decrease in Tc with Y content is due to redistribution of cations and weakening of the exchange coupling constant. The magnetic phase transition has been analyzed by Arrott plot and found to have second order phase transition. The dc resistivity endorses the prepared ferrites are suitable for high frequency and high temperature magnetic device applications as well.

Structural Characterization of Thin Epitaxial GaN Films on Polymer Polyimides Substrates by Ion Beam Assisted Deposition

The Epitaxial GaN thin films have been fabricated by Ion Beam Assisted Deposition (IBAD) process using nitrogen ions with hyperthermal energies on the polyimides polymer substrates. By applying with the Reflection of High-Energy Electron Diffraction (RHEED), Scanning Electron Microscopy (SEM) and Quantum Design Physical Properties Measurement System, the behaviour of hexagonal GaN thin films is investigated. The result showed that the high quality of the deposited GaN layers kept appearing for many parameters depending on the temperature greatly. The behaviour of high quality of epitaxial GaN coating on the polyimide polymer substrates is a promising material for optoelectronic devices and semiconductor devices application.

Low temperature anomalies and room temperature magnetism in In0.95Fe0.05Sb dilute magnetic semiconducting film

We report the results of structural, electrical, surface morphological, and magnetic studies on the undoped and dilute Fe (0.05) doped InSb films (In0.95Fe0.05Sb) using the grazing angle X-ray diffraction technique, the quantum design physical property measurement system, atomic force microscopy (AFM), magnetic force microscopy (MFM), and the quantum design magnetic property measurement system. The In0.95Fe0.05Sb film of 500 nm thickness is grown on the silicon (Si) substrate using the thermal evaporation technique. A systematic investigation of electrical resistivity as a function of temperature and magnetic field is embarked. The electrical resistivity of the respective sample exhibits an upturn at approximately 15 K in the ferrimagnetic region. This theory explains the anomalous behavior of the electrical resistivity based on electron-electron, electron-phonon, electron-magnon, and Kondo-like spin-dependent scattering. The high-temperature data above 300 K are interpreted using the adiabatic small polaron hopping model. The AFM study shows the uniform particle size distribution, whereas the magnetic interaction at the surface is seen through MFM. The zero-field cooled magnetization measurement shows the transition at ∼65 K. The hysteresis curve at 10 K shows the ferrimagnetic behavior of the In0.95Fe0.05Sb film with coercivity and residual magnetization values of ∼100 Oe and 6.8811 emu, respectively.

Extended temperature regions of multiferroicity in nanoscale CuO

We have measured the magnetic susceptibility and heat capacity of CuO nanoparticles (16 nm) from 2 K to 400 K using a Quantum Design Physical Properties Measurement System (PPMS). The magnetization curves, acquired at various field strengths from 0 Oe to 50 kOe, are similar to literature data of bulk and nanoscale CuO showing a minimum at about 150 K, an upturn as temperature approaches 0 K, and a broad maximum at high temperatures extending beyond 400 K. The heat capacity data between 200 K and 400 K show several broad peaks. The number of these peaks and the temperatures at which they occur differ significantly from the magnetic transitions known to exist in bulk CuO. To further investigate these transitions in nanoscale CuO, we performed temperature dependent x-ray diffraction (XRD) at temperatures from 90 K to 700 K from which lattice parameters as a function of temperature were derived using a Rietveld refinement. Although no phase transitions were observed in these data, changes in the slopes of the lattice parameters are apparent at the transition temperatures observed in the heat capacity and susceptibility measurements. The various transitions in the heat capacity data are attributed to competing ferromagnetic and antiferromagnetic interactions caused by structural properties that are unique to nanophase CuO, and the temperature range of multiferroicity in nanoscale CuO is shown to extend to temperatures higher than those observed for bulk CuO. The heat capacity and temperature dependent XRD measurements are the first of their kind to be reported for CuO nanoparticles.

Modular thermal Hall effect measurement setup for fast-turnaround screening of materials over wide temperature range using capacitive thermometry

We demonstrate a simple and easy-to-build probe designed to be loaded into a widely available Quantum Design Physical Properties Measurement System (PPMS) cryostat, with a detachable shielded sample puck section and robust heat sinking of three pairs of coaxial cables. It can be in principle used with any low-temperature cryostat. Our modular puck design has a radiation shield for thermal isolation and protection of the delicate sample space while handling and allows any variety of experimental setup benefiting from shielded coaxial wiring to be constructed on a selection of sample pucks. Pucks can be quickly and easily switched, and the system makes use of the simple yet extremely stable temperature and magnetic field control of the easy-to-use PPMS system. We focus on a setup designed for measurements of the thermal Hall effect and show that this system can yield unprecedented resolution over a wide temperature range and with rapid sample mounting or changing—allowing a large collection of potential samples to be screened for this novel physics. Our design aims to make these sensitive but challenging measurements quick, reliable, cheap, and accessible, through the use of a standard, widespread base cryostat and a system of modular removable sample stage pucks to allow quick turnaround and screening of a large number of candidate samples for potential new thermal Hall physics.

Crystal structure and thermochemical properties of cesium d-gluconate Cs[D-C6H11O7](s)

A novel coordination compound cesium d-gluconate, Cs[D-C6H11O7], have been synthesized and characterized by chemical analysis, elemental analysis, and X-ray diffraction technique. Single-crystal X-ray analysis reveals that the crystal of the compound is monoclinic with space group P21 and Z = 2. The d-gluconate anion in the compound of Cs[D-C6H11O7](s) has a bent-chain conformation, and exhibits an obvious chelate property of d-gluconate anions to cesium(І) cations. The lattice potential energy and ionic volume of the common anion are obtained from crystallographic data. The standard molar enthalpy of formation of the compound Cs[D-C6H11O7](s) is determined to be - (1789.21 ± 0.52) kJ mol−1 by use of an isoperibol solution-reaction calorimeter. The heat capacities of Cs[D-C6H11O7](s) were measured using a Quantum Design Physical Property Measurement System (PPMS) over the temperature range from (1.9–300) K, and the experimental values were fitted as a function of temperature using a series of theoretical and empirical models in the appropriate temperature ranges, from which the corresponding thermodynamic functions were calculated. The molar heat capacity, entropy and enthalpy of Cs[D-C6H11O7](s) at T = 298.15 K and P = 0.1 MP were determined to be Cp,m0=(204.93+2.05)J⋅K−1⋅mol−1, Sm0=(228.21+2.28)J⋅K−1⋅mol−1 and Hm0=(33.928+0.339)kJ⋅mol−1, respectively.

Comparison of Temperature and Field Dependencies of the Critical Current Densities of Bulk YBCO, MgB&lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$_2$&lt;/tex-math&gt; &lt;/inline-formula&gt;, and Iron-Based Superconductors

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