Dependence of the low-temperature specific heat of YBa2Cu3O7?? on ? and magnetic field: The H1/2T term for H?0; absence of evidence for a T2 term for H=0

d−WaveScaling Relations in the Mixed-State Specific Heat ofYBa2Cu3

“…The lattice contribution itself is not fully identified, as suggested by the widely dispersed values of the Debye temperature reported in the literature [5]. Therefore the detection of a minority contribution C T T electron / ∝ has to be based on indirect techniques such as differential measurements versus doping [6] [7], whereas multiparameter fits of the total specific heat give more ambiguous results [8] [9] [10]. Note also that the result C T T electron / ∝ is not general for d-wave symmetry, and may be modified by the angular dependence of the gap in the reciprocal space and by s+d mixing.…”

“…The entropy is field-independent both at T = 0 and T T c > , so that its The additional free energy due to d-wave vortices was calculated by Volovik [11], Kopnin and Volovik [27], and Volovik [14]. Two regimes are described, depending on the At variance with the assumption made earlier [8] [9] [10], the data for 12 10 . < < T K are not in the x << 1 regime because C T aniso / varies with T even in the highest fields (Fig.…”

Linear and quadratic temperature dependence of electronic specific heat for cuprates

“…[5] and references therein). In the second place, also at temperatures below T c , there is an αT 2 term in zero magnetic field [4,6,7] (initially denied in some reports [8]), which changes to a H 1/2 T component in the presence of an external magnetic field H, and is attributable to the superconducting part of the electronic specific heat. The reported values for this constant are of the order of tenths of mJ/mol K 3 [4], but as it happens for the linear term coefficient, the obtained values depend strongly on the conditions of each experiment and on the theoretical method each author uses to subtract the other specific heat components.…”