Evolution of a metastable phase with a magnetic phase coexistence phenomenon and its unusual sensitivity to magnetic field cycling in the alloys Tb5-xLuxSi3 (x <= 0.7)

TL;DR

This study investigates how small Lu substitutions in Tb5Si3 alloys influence magnetic phase coexistence, metastability, and unusual field sensitivity, revealing complex phase evolution and hysteresis behaviors at low temperatures.

Contribution

It demonstrates the evolution of magnetic anomalies and metastable phases in Tb5-xLuxSi3 alloys, highlighting the effects of composition and magnetic field cycling on phase stability.

Findings

Partial stabilization of high-resistivity phase after field cycling

Metastability and phase switch-over observed at low temperatures

Magnetic anomalies depend on composition and temperature

Abstract

Recently, we reported an anomalous enhancement of the positive magnetoresistance beyond a critical magnetic field in Tb5Si3 in the magnetically ordered state, attributable to 'inverse metamagnetism'. This results in unusual magnetic hysteresis loops for the pressurized specimens, which are relevant to the topic of 'electronic phase separation'. In this paper, we report the influence of small substitutions of Lu for Tb, to show the evolution of these magnetic anomalies. We find that, at low temperatures, the high-field high-resistivity phase could be partially stabilized on returning the magnetic field to zero in many of these Lu substituted alloys, as measured through the electrical resistivity ({\rho}). Also, the relative fractions of this phase and the virgin phase appear to be controlled by a small tuning of the composition and temperature. Interestingly, at 1.8 K a sudden 'switch-over' of the value of {\rho} for this mixed phase to that for the virgin phase for some compositions is observed at low fields after a few field cycles, indicating metastability of this mixed phase.