The Tricritical Point of the f-electron Antiferromagnet USb2 Driven by High Magnetic Fields

TL;DR

This study investigates the magnetic phase transitions in USb2 under high magnetic fields, identifying a tricritical point where the nature of the transition changes, influenced by f-p hybridization and magnetoelastic effects.

Contribution

It provides the first detailed experimental evidence of a tricritical point in USb2 driven by high magnetic fields and temperature.

Findings

Identification of a field-induced metamagnetic transition.

Observation of a change from second- to first-order transition near T_{tc} ~145K.

Decreased magnetic moment at high fields due to hybridization and magnetoelastic effects.

Abstract

In pulsed magnetic fields up to 65T and at temperatures below the N\'eel transition, our magnetization and magnetostriction measurements reveal a field-induced metamagnetic-like transition that is suggestive of an antiferromagnetic to polarized paramagnetic or ferrimagnetic ordering. Our data also suggests a change in the nature of this metamagnetic-like transition from second- to first-order-like near a tricritical point at T_{tc} ~145K and H_{c}~52T. At high fields for H>H_{c} we found a decreased magnetic moment roughly half of the moment reported in low field measurements. We propose that \mathit{f-p} hybridization effects and magnetoelastic interactions drive the decreased moment, lack of saturation at high fields, and the decreased phase boundary.