D-WAVE SPECIFIC-HEAT IN Y-123 AND BI-2212 SINGLE-CRYSTALS - NEW DATA,ALTERNATIVE EXPLANATION

The low temperature specific heat of Bi-2212 and Y-123 is measured for 1.2 less than or equal to T less than or equal to 7K and 0 less than or equal to B less than or equal to 14 T. We find that the field-induc ed ''linear'' term gamma(B)-gamma*(0) near 1-3K saturates for B great er than or equal to 8 T, decreases as a function of temperature, and h as nearly the same amplitude for both compounds. This is not easily re conciled with the predicted d-wave contribution C proportional to gamm a T(B/B-c2)(1/2). Oscillations of 2D vortices offer an alternative exp lanation.