Weak magnetic anisotropy in GdRh$_2$Si$_2$ studied by magnetic resonance

TL;DR

This study investigates the magnetic resonance properties of GdRh$_2$Si$_2$, revealing weak magnetic anisotropy in its antiferromagnetic state through detailed resonance measurements and mean-field analysis.

Contribution

It provides the first detailed characterization of magnetic anisotropy in GdRh$_2$Si$_2$'s AFM phase using microwave resonance techniques.

Findings

Paramagnetic resonance becomes anisotropic below 107 K.

Internal exchange fields are small, enabling detailed resonance analysis.

Weak in-plane anisotropy characterized in ferromagnetic layers.

Abstract

The antiferromagnetically (AFM) ordered state of GdRh$_{2}$Si$_{2}$ which consists of AFM-stacked ferromagnetic layers is investigated by magnetic resonance spectroscopy. The almost isotropic Gd$^{3+}$ paramagnetic resonance becomes anisotropic in the AFM ordered region below 107 K. The emerging internal anisotropic exchange-fields are still small enough to allow an investigation of their magnetization dynamics by using a standard microwave-frequency magnetic resonance technique. We could characterize this anisotropy in detail in the ferromagnetic layers of the excitation at 9 and 34 GHz. We derived a resonance condition for the AFM ordered phase to describe the weak in-plane anisotropic behaviour in combination with a mean-field analysis.