Investigation of magnetic flux gradients in hard superconductors

Analytical calculations of the transverse magnetostriction in a thin hard s uperconductor are presented in relation to the distributions of currents an d fields within a superconducting specimen in a varied magnetic field. The approach is successfully tested on high-temperature superconductors. The fl ux distribution derived from magnetostriction measurements is in satisfacto ry agreement with that obtained from computer processing of magnetooptical images. The magnetic flux distribution below the irreversibility line of ha rd superconductors is derived from both original magnetization and magnetos triction measurements and image processing. Perfect consistency of the resu lts is obtained for a family of high-temperature superconductors (La2-xSrxC uO4, Bi2Sr2CaCu2Ox, YBa2Cu3O7-delta). (C) 2001 American Institute of Physic s.