The specific heat of YBa2Cu3O7-delta: evidence for d-wave pairing

The specific-heat (C) of two polycrystalline samples of YBa2Cu3O7 - delta i s reported for 0.8 < 12 K, magnetic fields (H) to 9 T, and 0 less than or e qual to delta less than or equal to 0.2. The data confirm a number of effec ts predicted for d-wave pairing: for H = 0, a T-2 term; for H not equal 0 a nd H-1/2T less than or similar to 6.5 T-1/2 K, an (HT)-T-1/2 term; for H-1/ 2T similar to 6.5 T-1/2 K, a crossover to a more complicated H and T depend ence; for all H and T, agreement with a proposed scaling relation, C-DOS/(( HT)-T-1/2)= F(H-1/2T), where F is an undetermined scaling function and Coos is the electron density of states (DOS) contribution to C. (C) 1999 Elsevi er Science B.V. All rights reserved.