Events

Seminar of International Laboratory of High Magnetic Fields and Low Temperatures PAS

Magnetization and critical current of calcium-doped YBa₂Cu₃O_7-x composite films

I.A. Rudnev, A.P. Menushenkov, A.V. Blednov, V.N. Chepikov, S.V. Samoylenkov

National Research Nuclear University MEPHI (Mos-cow Engineering Physics Institute), Moscow, Russia

In the report we present results of the study of magnetization of Y_1-хCa_xBa₂Cu₃O_7-d HTS films deposited on the metallic substrate. Magnetisation measurements were carried out in a wide temperature range 4 – 77 K and magnetic fields up to 14 T. Based on critical state model the analysis of the influence the effect of calcium concentration on the critical current in the samples was performed. It was found that the change in Ca concentration causes the decrease in value of critical current density j_c. The increase of temperature leads to an enhancement of the observed effect. At T = 4.2 K and in the magnetic fields higher than 8 T the j_c reduction was found to be insignificant. This fact may indicate the possibility of j_c growth in strong magnetic fields due to increase in carrier concentration caused by replacing Y³⁺ by Ca^{2 +}.