相关论文: Calorimetric Investigation of NdBa2Cu3Ox Single Cr…
We present detailed heat capacity measurements for Ba(Fe(1-x)Cox)2As2 and Ba(Fe(1-x)Nix)2As2 single crystals in the vicinity of the superconducting transitions. The specific heat jump at the superconducting transition temperature (Tc),…
We present high-resolution capacitance dilatometry studies from 5 - 500 K of untwinned YBa2Cu3Ox (Y123) single crystals for x ~ 6.95 and x = 7.0. Large contributions to the thermal expansivities due to O-ordering are found for x ~ 6.95,…
We have measured the specific heat of crystals of (Ca1-xSrx)3Ru2O7 using ac- and relaxation-time calorimetry. Special emphasis was placed on the characterization of the Neel (TN=56 K) and structural (Tc = 48 K) phase transitions in the…
The specific heat of single crystal hole-doped Ca0.33Na0.67Fe2As2, Tc(onset)=33.7 K, was measured from 0.4 to 40 K. The discontinuity in the specific heat at Tc, deltaC, divided by Tc is 105 +- 5 mJ/molK2, consistent with values found…
LaBaCaCu3O7 (La:1113) and NdBaCaCu3O7 (Nd:1113) compounds are synthesized by solid state reaction route. Both compounds crystallize in tetragonal structure. Four probe resistivity measurements showed that superconducting transition…
In YBa2Cu3Ox, distinct features are found in the pressure dependence of the transition temperature, dTc/dp, and in DeltaCp*Tc, where DeltaCp is the jump in the specific heat at Tc: dTc/dp becomes zero when DeltaCp*Tc is maximal, whereas…
The linear compressibilities and the thermal expansion of an untwinned, nearly optimal doped YBa2Cu3O6.94 single crystal were measured along the three crystallographic axes with a high-resolution dilatometer mounted in a high-pressure cell.…
We studied Tc of YBa2Cu3Ox (Y123), Y0.89Ca0.11Ba2Cu3Ox (YCa123) and NdBa2Cu3Ox (Nd123) single crystals with various oxygen contents x. Compared to Tc(x) of Y123 the Tc(x) curves of YCa123 are shifted to lower oxygen contents and the maximum…
A scan of the superconductor -- nonsuperconductor transformation in single crystals YBa_2Cu_3O_{6+x} (x about 0.37) was done in two alternative ways, namely, by applying the magnetic field and by reducing the hole concentration through the…
Thermochemical characteristics of Nd1+xBa2-xCu3Oy solid solutions were studied by solution calorimetry. Dependences of formation enthalpies from Nd content were constructed. It was established that decomposition of solid solution on the…
The strong coupling of superconductivity to the orthorhombic distortion in YBa2Cu3O7-d makes possible an analysis of the superconducting fluctuations without the necessity of subtracting any background. The present high-resolution…
In accordance with a relation between the lattice parameter c and the concentration of holes p, which has been found earlier for the YBa2Cu3O6+d compound, we obtain the p parameter in the same manner for the solid solution Nd1.2Ba1.8Cu3O6+d…
The specific heat $C(T)$ of BaFe$_2$As$_2$ single crystal, electron-doped Ba$_{0.7}$La$_{0.3}$Fe$_2$As$_2$ and hole-doped Ba$_{0.5}$K$_{0.5}$Fe$_2$As$_2$ polycrystals were measured. For undoped BaFe$_2$As$_2$ single crystal, a very sharp…
High-purity and homogeneous YBa2Cu3Oy single crystals with carrier doping level near the AFM-SC boundary have been obtained in the oxygen content range between y = 6.340 and 6.370. The crystals are ortho-II phase at room temperature and…
Single Crystals of Nd$_{1-x}$Ca$_{1+x}$MnO$_{4}$ have been prepared by the traveling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High…
The oxygenation process at constant temperature of YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) was systematically investigated in the temperature range from 300 $^o$C to 800 $^o$C. With this purpose, fully deoxygenated powder samples was exposed to…
Distinct discontinuities in the thermal expansion of the crystal lattice are observed at the melting-transition of the vortex lattice in a naturally untwinned reversible YBa2Cu3O7-d-single crystal using high-resolution dilatometry. This…
The superconducting transition in a single overdoped, detwinned YBa2Cu3Ox (YBCO) crystal is studied using four different probes. Whereas the AC and DC magnetic susceptibilities find a dominant transition at 88 K with a smaller effect near…
A superconducting transition in the temperature dependence of the ab-plane resistivity of underdoped YBa_2Cu_3O_{6+x} crystals in the range T_c<30 K has been investigated. Unlike the case of samples with the optimal level of doping, the…
We discovered the enhancement of superconducting transition temperature, Tc, in yttrium sesquicarbide system with the maximum Tc of Tc=18K and their superconducting properties were discussed. The crystal structure of Y2C3 is the…