Magnetic properties of a superconducting Ba-La-Cu oxide

Abstract

Magnetic measurements have been carried out on a novel system of overall composition ${\mathrm{Ba}}_{0.15}$ ${\mathrm{La}}_{1.85}$ ${\mathrm{CuO}}_4$+0.${13\mathrm{L}\mathrm{a}}_2$ ${\mathrm{O}}_3$ in the temperature range between 5 and 40 K. Both dc and ac magnetic susceptibilities show the onset of diamagnetism around 27 K. The magnetic flux trapping for samples cooled in a magnetic field has been observed up to ∼29 K. The observed magnetic behavior follows the prediction of Ebner and Stroud [Phys. Rev. B 31, 165 (1985)] for growing superconducting clusters.