Electron spin resonance in spiral antiferromagnet linarite: theory and experiment

TL;DR

This paper combines experimental and theoretical methods to study low-frequency ESR dynamics in the spiral antiferromagnet linarite, revealing how magnetic anisotropy influences exotic quantum states.

Contribution

It provides a detailed analysis of ESR frequencies and anisotropy constants in linarite, advancing understanding of its magnetic phases and quantum state potential.

Findings

Resonance frequencies depend on magnetic field and orientation.

Magnetic anisotropy constants are precisely determined.

Biaxial anisotropy influences the realization of multipolar quantum states.

Abstract

We present combined experimental and theoretical investigation of the low-frequency ESR dynamics in the ordered phases of magnetic mineral linarite. This material consists of weakly coupled spin-1/2 chains of copper ions with frustrated ferro- and antiferromagnetic interactions. In zero magnetic field, linarite orders into a spiral structure and exhibits a peculiar magnetic phase diagram sensitive to the field orientation. The resonance frequencies and their field dependence are analyzed combining microscopic and macroscopic theoretical approaches and precise values of magnetic anisotropy constants are obtained. We conclude that possible realization of exotic multipolar quantum states in this material is greatly influenced by the biaxial anisotropy.