Specific heat peaks observed up to 16 T on the melting line of the vortex lattice in YBa2Cu3O7

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

“…The calorimetric transition midpoint T c ≅ 87 5 . K [13] was typical of overdoped YBa 2 Cu 3 O 7.00 . The high chemical purity and the low concentration of oxygen vacancies should both favour the observation of d-wave properties in the clean limit ; such requirements were also found to be essential for the calorimetric observation of a transition in the vortex lattice [13].…”

“…This shift has a dramatic effect on the DOS when the gap is small, so that the essential contribution comes from the vicinity of the nodes. In a low temperature limit that will be specified later, the DOS at E F becomes proportional to B In order to get rid of the uncertainties introduced by multiparameter fits, essentially due to the fact that the analytic form of some contributions is unclear, we look at the anisotropic overdoped crystal [13], so that we still obtain a large fraction of the full vortex specific heat.…”

“…The new level of purity of such samples, 99.995% [17], has allowed successful experiments such as imaging the vortex lattice by scanning tunnelling microscopy [18], suppression of the magnetic « fishtail » effect [19], observation of specific heat peaks at the flux line lattice melting transition in fields up to 16 T [13], etc. The 18 mg single crystal used for the present study (and also in Refs.…”

“…The 18 mg single crystal used for the present study (and also in Refs. [13] and [19], code AE195G) was fully oxygenated in 100 bars O 2 at 300°C. The calorimetric transition midpoint T c ≅ 87 5 .…”

Specific heat of underdoped cuprate superconductors from a phenomenological layered Boson–Fermion model

“…The reported values for this two constants depend strongly on the conditions of each experiment [17] and on the theoretical method used to relate the different parts of the total specific heat. Thirdly, there is a "jump" in the constant pressure specific heat [21] C p at T c (at zero magnetic field and evolving into a "peak" at finite magnetic field), ∆C p /T c , attributable to the C es component, indicating a second order phase transition which in turn becomes a smooth maximum as doping decreases [22]. Finally, as the "upturn" in the specific heat at very low temperatures is suppressed, a cubic term ßT 3 is also observed [23].…”