Resonances in a dilute gas of magnons and metamagnetism of isotropic frustrated ferromagnetic spin chains

TL;DR

This paper investigates how quantum fluctuations and frustration induce metamagnetic transitions in isotropic ferromagnetic spin chains, revealing a first-order magnetization jump influenced by magnon resonances near a Lifshitz point.

Contribution

It demonstrates that dilute magnon resonances cause metamagnetism in SU(2)-symmetric ferromagnetic chains with frustration, highlighting the role of quantum effects and frustration in magnetic phase transitions.

Findings

Metamagnetic behavior occurs for small spin S under an external magnetic field.

Magnetization jumps are influenced by a ferromagnetic Lifshitz point.

Resonances in the dilute magnon gas drive the first-order transition.

Abstract

We show that spin-S chains with SU(2)-symmetric, ferromagnetic nearest-neighbor and frustrating antiferromagnetic next-nearest-neighbor exchange interactions exhibit metamagnetic behavior under the influence of an external magnetic field for small S, in the form of a first-order transition to the fully polarized state. The corresponding magnetization jump increases gradually starting from an S-dependent critical value of exchange couplings and takes a maximum in the vicinity of a ferromagnetic Lifshitz point. The metamagnetism results from resonances in the dilute magnon gas caused by an interplay between quantum fluctuations and frustration.