Torque magnetometry studies of metamagnetic transitions in single-crystal HoNi_{2}B_{2}C and ErNi_{2}B_{2}C at T\approx 1.9 K

TL;DR

This study uses torque magnetometry to explore metamagnetic transitions in single-crystal HoNi₂B₂C and ErNi₂B₂C at 1.9 K, revealing angular dependence and new features of their magnetic states.

Contribution

It provides detailed angular diagrams and uncovers new magnetic behaviors, including multidomain effects and angular-dependent transition sequences.

Findings

Critical fields depend on field angle and easy axis.

Discovered influence of multidomain states and frustration near hard axes.

Sequence of metamagnetic states varies with field orientation.

Abstract

The metamagnetic transitions in single-crystal rare-earth nickel borocarbide HoNi_{2}B_{2}C and ErNi_{2}B_{2}C have been studied at 1.9 K with a Quantum Design torque magnetometer. The critical fields of the transitions depend crucially on the angle between applied field and the easy axis [110] for HoNi_2B_2C and [100] for ErNi_2B_2C. Torque measurements have been made while changing angular direction of the magnetic field (parallel to basal tetragonal ab-planes) in a wide angular range (more than two quadrants). The results are used not only to check and refine the angular diagram for metamagnetic transitions in these compounnds, but also to find new features of the metamagnetic states. Among new results for the Ho borocarbide are the influence of a multidomain antiferromagnetic state, and ``frustrated'' behavior of the magnetic system for field directions close to the hard axis [100]. Torque measurements of the Er borocarbide clearly show that the sequence of metamagnetic transitions with increasing field (and the corresponding number of metamagnetic states) depends on the angular direction of the magnetic field relative to the easy axis.