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

MARCELO ARLEGO; FABIAN HEIDRICH-MEISNER; ANDREAS HONECKER; GERARDO ROSSINI; TEIMURAZ VEKUA

Natal

Workshop; Geometrically Frustrated Magnets: from spin ice to kagome planes; 2011

UFRN Universidade Federal do Rio Grande do Norte

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