Angular dependent planar metamagnetism in the hexagonal compounds TbPtIn and TmAgGe

TL;DR

This study investigates the angular dependence of metamagnetic transitions in the hexagonal compounds TbPtIn and TmAgGe, revealing multiple phases and modeling their magnetic behavior with a three coplanar Ising-like framework.

Contribution

The paper introduces a detailed angular-dependent magnetization analysis and a novel three coplanar Ising-like model for these compounds, advancing understanding of their metamagnetic phenomena.

Findings

Identification of easy magnetization axes in both compounds.

Observation of five metamagnetic transitions with angular dependence.

Modeling of magnetization and critical fields using a three coplanar Ising-like approach.

Abstract

Detailed magnetization measurements, M(T,H,theta), were performed on single crystals of TbPtIn and TmAgGe (both members of the hexagonal Fe_2P/ZrNiAl structure type), for the magnetic field H applied perpendicular to the crystallographic c axis. These data allowed us to identify, for each compound, the easy-axes for the magnetization, which coincided with high symmetry directions ([120] for TbPtIn and [110] for TmAgGe). For fixed orientations of the field along each of the two six-fold symmetry axes, a number of magnetically ordered phases is being revealed by M(H,T) measurements below T_N. Moreover, T ~ 2 K, M(H)|_theta measurements for both compounds (with H applied parallel to the basal plane), as well as T = 20 K data for TbPtIn, reveal five metamagnetic transitions with simple angular dependencies: H_{ci,j} ~ 1/cos(theta +/- phi), where phi = 0^0 or 60^0. The high field magnetization state varies with theta like 2/3*mu_{sat}(R^{3+})*cos(theta), and corresponds to a crystal field limited saturated paramagnetic, CL-SPM, state. Analysis of these data allowed us to model the angular dependence of the locally saturated magnetizations M_{sat} and critical fields H_c with a three coplanar Ising-like model, in which the magnetic moments are assumed to be parallel to three adjacent easy axes. Furthermore, net distributions of moments were inferred based on the measured data and the proposed model.