Separation of energy scales in the kagome antiferromagnet TmAgGe: a magnetic-field-orientation study up to 55 T

TL;DR

This study investigates the magnetic behavior of TmAgGe, revealing two distinct energy scales responsible for metamagnetic transitions through high-field, angle-dependent magnetization measurements and simulations.

Contribution

It identifies and characterizes the separate roles of exchange and crystalline electric field interactions in TmAgGe's magnetic transitions, providing new insights into its energy scale separation.

Findings

Two separate energy scales govern metamagnetic transitions.

Simulations clarify the physical origin of transitions in low in-plane fields.

Transitions with perpendicular fields relate to CEF-split multiplet of Tm.

Abstract

TmAgGe is an antiferromagnet in which the spins are confined to distorted kagome-like planes at low temperatures. We report angle-dependent measurements of the magnetization $M$ in fields of up to 55 T that show that there are two distinct and separate energy scales present in TmAgGe, each responsible for a set of step-like metamagnetic transitions; weak exchange interactions and strong crystalline electric field (CEF) interactions. Simulations of $M$ using a three-dimensional, free-energy minimization technique allow us to specify for the first time the physical origin of the metamagnetic transitions in low, in-plane fields. We also show that the transitions observed with the field perpendicular to the kagome planes are associated with the CEF-split multiplet of Tm.