MAGNETIZATION SCALING ON THICK YBA2CU3O7-X SINGLE-CRYSTALS

Magnetic-hysteresis curves of YBa2Cu3O7-x single crystals are found to exhibit scaling features. The scaling parameters, the full penetratio n field H-p, and the associated magnetization M(p), are determined exp erimentally as the merging point between the virgin magnetic curve and the M-H loop envelope. Scaling is performed by dividing M and H by M( p) and H-p, respectively. For magnetic fields higher than H-p, the M-H loops, once scaled, lie on a unique envelope, independent of temperat ure up to the irreversibility line. This result suggests that there is no evidence of any phase transition for H > H-p. This scaling has bee n performed on the data obtained for two YBa2Cu3O7-x single crystals, one oxygenated under atmospheric pressure and the other one under high oxygen pressure. The results have shown that pinning in the latter cr ystal is more effective at intermediate magnetic fields, H similar to H-p, but less effective at fields H significantly higher than H-p.