Enhancement of positive magnetoresistance following a magnetic-field-induced ferromagnetic transition in an intermetallic compound, Tb5Si3

TL;DR

This study reveals a field-induced ferromagnetic transition in Tb5Si3 that unexpectedly increases electrical resistivity, leading to enhanced positive magnetoresistance across a range of temperatures, with the transition's order changing with temperature.

Contribution

It demonstrates a novel positive magnetoresistance effect associated with a magnetic-field-induced transition in Tb5Si3, highlighting a temperature-dependent change in the transition's nature.

Findings

Ferromagnetic transition occurs near 60 kOe below 69 K.

Electrical resistivity increases sharply after the transition.

Positive magnetoresistance is observed unexpectedly in the high-field state.

Abstract

We report the existence of a field-induced ferromagnetic transition in the magnetically ordered state (<69 K) of an intermetallic compound, Tb5Si3, and this transition is distinctly first-order at 1.8 K (near 60 kOe), whereas it appears to become second order near 20 K. The finding we stress is that the electrical resistivity becomes suddenly large in the high-field state after this transition and this is observed in the entire temperature range in the magnetically ordered state. Such an enhancement of 'positive' magnetoresistance (below 100 kOe) at the metamagnetic transition field is unexpected on the basis that the application of magnetic field should favor a low-resistive state due to alignment of spins.