Influence of pressure on the magnetic behavior and the anomalous magnetoresistance in Tb5Si3

TL;DR

This study explores how external and chemical pressures affect the magnetic and magnetoresistive properties of Tb5Si3, revealing persistent resistivity anomalies linked to magnetic fluctuations at critical fields.

Contribution

It provides new insights into pressure effects on magnetoresistance and critical magnetic fields in Tb5Si3, highlighting the role of magnetic fluctuations in these phenomena.

Findings

Resistivity anomaly persists under pressure and chemical substitution.

Negative pressure derivative of critical magnetic field H_cr.

Magnetoresistance behavior similar to Laves phase systems.

Abstract

The compound, Tb5Si3, crystallizing in Mn5Si3-type hexagonal structure, was recently reported by us to exhibit a sudden and huge enhancement in electrical resistivity (rho) at a critical magnetic field (H_cr) in the magnetically ordered state (<70 K) tracking isothermal magnetization (M) behavior. We have investigated the influence of external pressure (<15 kbar) and negative chemical pressure induced by Ge substitution for Si on M and rho as a function of temperature (5-300 K) and magnetic field (<120 kOe), with the primary aim of understanding the field-induced anomalies. Focussing on isothermal M and magnetoresistance (MR) at two temperatures, 5 and 20K, we find that this rho anomaly persists under external as well as negative chemical pressures, however with a large change in the H_cr. The pressure-derivative of H_cr is negative and this trend and the MR behavior at the H_cr are comparable to that observed in some Laves phase itinerant magnetic systems. On the basis of this observation, we speculate that the magnetic fluctuations induced at this critical field could be responsible for the MR anomal.ies