Dual role of an ac driving force and the underlying two distinct order-disorder transitions in the vortex phase diagram of Ca3Ir4Sn13

TL;DR

This study investigates the complex vortex phase transitions in Ca3Ir4Sn13, revealing how an ac magnetic field influences the transition from Bragg glass to vortex glass and the nature of the phase changes.

Contribution

It provides new insights into the dual role of ac driving forces and distinguishes two separate order-disorder vortex transitions in a superconducting material.

Findings

Ac magnetic field assists BG to VG transition near SMP anomaly.

BG phase can be superheated, indicating first-order transition.

Distinct demarcation of vortex phase boundaries in Ca3Ir4Sn13.

Abstract

We present distinct demarcation of the Bragg glass (BG) to multi-domain vortex glass (VG) transition line and the eventual amorphization of the VG phase in a weakly pinned single crystal of the superconducting compound Ca3Ir4Sn13 on the basis of comprehension of the different yields about the second magnetization peak (SMP) anomaly in the dc magnetization and the corresponding anomalous feature in the ac susceptibility measurements. The shaking by a small ac magnetic field, inevitably present in the ac susceptibility measurements, is seen to result in contrasting responses in two different portions of the field-temperature (H, T) phase space of the multi-domain VG. In one of the portions, embracing the BG to VG transition across the onset of the SMP anomaly, the ac drive is surprisingly seen to assist the transformation of the well ordered BG phase to a lesser ordered VG phase. The BG phase exists as a superheated state over a small portion of the VG space and this attests to the first order nature of the BG to VG transition.