INTERMEDIATE TRANSITIONS IN AS-GROWN MTG SINGLE-CRYSTAL YBCO

Measurements of the intermediate superconducting transitions seen in A C susceptibility measurements of directionally solidified ''single cry stals'' of YBCO have been made for the fields parallel and perpendicul ar to the c-axis. The results show a high degree of correlation betwee n the different directions, and these have been interpreted in terms o f the screening-current loops associated with each orientation. The am plitude dependence of the peak positions for AC magnetic fields in the range 70-350 mOe follow the general rule h0 = beta((T(i)-T(m))/T(i))1 .