Enhancement of intrinsic pinning in the high-temperature superconductor TmBa2Cu3Oy: manifestation of the interaction between vortices and a magnetic rare-earth ion

Abstract The magnetic-field dependences of the low-frequency complex permeability have been measured for thin-plate single crystals of the high-temperature superconductor TmBa2Cu3Oy in a static external magnetic field H and an alternating magnetic field with the amplitude h (h