Rectifying the second magnetization peaks. Comments on “Revealing the vortex phases and second magnetization peaks in SmBCO superconductors” [J. Appl. Phys. 136, 173904 (2024)]

Abstract

A recent study, “Revealing the vortex phases and second magnetization peaks in SmBCO superconductors” published in J. Appl. Phys. 136 (2024), presents detailed resistance and magnetization measurements of a single-crystal Sm-based high-Tc superconductor at different temperatures and magnetic fields. Based on these measurements, the authors constructed the vortex phase diagram and discussed the pinning mechanism. Due to the significance of this research area, clarifications concerning pinning force curves Fp(H) estimated from magnetization hysteresis loops must be addressed. A peak located near the highest applied field does not necessarily demonstrate the maximal pinning force. The peak position only corresponds to the maximal pinning force when the highest applied field is close to or greater than the irreversibility field Hirr.