Specific heat field dependence

Figure 4.7 Temperature dependence of the contribution to the total specific heat, reveals magnetization in 5 0e applied field of a pow- two distinct phase transitions. (Redrawn der sample of Gd(hfac)3NIT-Et n evidencing from Ref. [53] with data kindly provided by a phase transition around 1.8K. In the inset A. Lascialfari. (Published by American the magnetic contribution to the specific physical society).) heat, evaluated by subtracting the lattice...

We wish also to mention the discovery of an unusual magnetic field dependence of specific heat in some multicomponent glasses in the 0.3 tK range [46]. A theoretical explanation of the phenomenon can be found in ref. [[47] pp. 17-46]. 

Besides the crust and the hadron shell, the hybrid star contains also a quark core. Both the nucleon shell and the quark core can be in superconducting phases, in dependence on the value of the temperature. Fluctuations affect transport coefficients, specific heat, emissivity, masses of low-lying excitations and respectively electromagnetic properties of the star, like electroconductivity and magnetic field structure, e.g., renormalizing critical values of the magnetic field (/ ,, Hc, Hc2). 

Sample shape refers to the shape of the whole ensemble of nanoparticles, not to the shape of the individual particles. The linear susceptibility exhibits a sample shape dependence, while the zero-field specific heat and the dipolar fields do not. 

Fig. 19. Temperature dependence of the specific heat of UAs for constant magnetic field applied along the (001) axis. (Rossat-Mignod et al. ))...

S5 — Sjv)r—o = yT- The behaviour of y in the superconducting state is different from that of the normal state y is a linear function of temperature in the normal state but its temperature dependence is exponential in the superconducting state. The superconducting transition at zero magnetic field is a second-order phase transition since there is discontinuity in specific heat but no latent heat change. 

Fig. 38. (a) Resistivity vs. temperature measured at different magnetic fields H on a polycrystalline HoNi2B2C sample. Tc is the superconducting transition temperature at H = 0. A near-reentrant behaviour occurs around a temperature Tn. (b) Temperature dependence of the specific heat Cp of a HoNi2B2C single crystal (2 mm x 3 mm x 0.1 mm in size), measured at zero magnetic fiekL Above the main peak of Cp(T) at Tn. two additional features appear (marked by arrows). Samples prepared by I. Freudenberger. 

Fig. 47. (a) Temperature dependence of the specific heat C as aC/T-vs.-T2 plot for TmNi2B2C. The maximum at 7"c indicates the transition to superconductivity and the low-temperature upturn is related to magnetic ordering. The solid line is calculated taking into account contributions from phonons and crystal field levels (b) specific heat of TmNi2B2C at low temperatures with a maximum at Tn (after Movshovich et al. 1994). 

An unexpected concentration dependence is found for the parameter which describes, according to eq. (8), the deviation of the field dependence of the electronic specific heat in the mixed state from the linear law expected (Nohara et al. 1997) for isotropic s-wave superconductors in the dirty limit. The large deviations from this linear y(H) law observed... 

Fig. 60. Concentration dependence of various properties of polycrystalline Y(Ni xPt )2B2C obtained by specific heat measurements transition temperature Tc exponent a and parameter Hc2 from eq. (6) upper critical field Hc2(0) at T =0, where the dotted line schematically describes the dirty limit corresponding to the isotropic single band case (in reality there is a finite intersection with the field-axis for the dotted asymptotic line, see Shulga and Drechsler 2002) exponent fi of eq. (8) for the curvature of the electronic specific heat in the mixed state and Sommerfeld constant xn (after Lipp et al. 2001).

Fig. 61. Magnetic field dependence of the specific heat contribution y(H) of the vortex core electrons in the mixed state for Y(Nio.7sPto.25)2B2C. The dashed line is a fit according to eq. (8) with /) = 0.17, the solid line corresponds to the y(H)

Despite the previously debated d-wave symmetry of the superconducting gap in YNi2B2C as suggested from the interpretation of specific-heat (Cp) data (Nohara et al., 1997), additional mechanisms for the T3 dependence of the electronic part of Cp and its unusual magnetic-field dependence were discussed, including the shrinking of the vortex core radius with increasing field (Nohara et al., 1999). The influence of disorder is discussed in Section 6.2. Measurements of the microwave... 

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