Magnetic properties of bulk melt-textured YBa2Cu3O7 prepared in a sola
r furnace were investigated. The material obtained demonstrates high c
ritical Current density of the order of 10(5) A/cm(2) in the field of
a 1 T at 50 K. The effective activation energy for flux creep was calc
ulated using Maley's approach and fits the universal relation: U-eff=U
(0)G(T)(J/J(c))(-n), where n=3/2, which agrees with the result predict
ed by the collective flux creep theory. (C) 1996 American Institute of
Physics.