Thermodynamic evidence for the Bose glass transition in twinned YBa$_2$Cu$_3$O$_{7-\delta}$ crystals

TL;DR

This study provides thermodynamic evidence for the Bose glass transition in twinned YBa2Cu3O7−δ crystals by measuring magnetic response anomalies near the transition.

Contribution

It presents direct thermodynamic measurements indicating the Bose glass transition in high-temperature superconductor crystals, a novel experimental confirmation.

Findings

Anomaly in magnetization temperature dependence observed

Magnetic shielding perpendicular to twin boundaries detected

Transition from vortex liquid to Bose glass confirmed

Abstract

We used a micromechanical torsional oscillator to measure the magnetic response of a twinned YBa$_2$Cu$_3$O$_{7-\delta}$ single crystal disk near the Bose glass transition. We observe an anomaly in the temperature dependence of the magnetization consistent with the appearance of a magnetic shielding perpendicular to the correlated pinning of the twin boundaries. This effect is related to the thermodynamic transition from the vortex liquid phase to a Bose glass state.