Unveiling of Bragg glass to vortex glass transition by an ac driving force in a single crystal of Yb3Rh4Sn13

TL;DR

This study reveals that an ac driving force in a Yb3Rh4Sn13 superconductor promotes a transition from an ordered Bragg glass to a disordered vortex glass at lower fields, contrasting with dc measurements that show different transitions.

Contribution

It uncovers the counterintuitive role of ac drive in inducing disorder in vortex matter, highlighting discrepancies between ac and dc magnetization results in a low Tc superconductor.

Findings

Ac drive promotes BG to VG transition at lower fields.

Dc magnetization does not reveal the BG to VG transition.

Peak effect indicates emergence of ordered vortex phase above a certain field.

Abstract

We present here some striking discrepancies in the results of ac and dc magnetization measurements performed in a single crystal of low Tc superconductor, Yb3Rh4Sn13. Fingerprint of a transition from an ordered vortex lattice a la Bragg glass (BG) phase to a partially-disordered vortex glass (VG) like phase gets unearthed under the influence of an ac driving force present inevitably in the isothermal ac susceptibility measurements. In contrast to its well-known effect of improving the state of spatial order in the vortex matter, the ac drive is surprisingly found to promote disorder by assisting the BG to VG transition to occur at a lower field value in this compound. On the other hand, the isothermal dc magnetization (M-H) scans, devoid of such a driving force, do not reveal this transition; they instead yield signature of another order-disorder transition at elevated fields, viz., peak effect (PE), located substantially above the BG to VG transition observed in the isothermal ac susceptibility measurements. Further, the evolution of PE feature with increasing field as observed in isofield ac susceptibility plots indicates emergence of an ordered vortex configuration (BG) from a disordered phase above a certain field, H* (~ 4 kOe). Below H*, the vortex matter created via field-cooling (FC) is found to be better spatially ordered than that prepared in zero field-cooled (ZFC) mode. This is contrary to the usual behavior anticipated near the high-field order-disorder transition (PE) wherein a FC state is supposed to be a supercooled disordered phase and the ZFC state is comparatively better ordered.