Metastable states in the triangular-lattice Ising model studied by Monte Carlo simulations: Application to the spin-chain compound Ca3Co2O6

Soto R.; Martinez, G; Baibich, MN; Florez, JM; Vargas, P.

Abstract

It is well known that the spin-chain compound Ca3 Co2 O6 exhibits interesting plateaus in the magnetization as a function of the magnetic field at low temperatures. The origin of them is still controversial. In this paper, we study the thermal behavior of this compound with a single-flip Monte Carlo simulation on a triangular lattice and demonstrate the decisive influence of metastable states on the splitting of the ferrimagnetic 1/3 plateau below 10 K. We consider the [Co2 O6] n chains as giant magnetic moments described by large Ising spins on planar clusters with open boundary conditions. With this simple frozen-moments model we obtain stepped magnetization curves which agree quite well with the experimental results for different sweeping rates. We describe particularly the out-of-equilibrium states that split the low-temperature 1/3 plateau into three steps. They relax thermally to the 1/3 plateau, which has long-range order at equilibrium. Such metastable states are further analyzed with snapshots unveiling an interlinked mobile domain walls structure that is responsible for the observed behavior of the 1/3 plateau. A comparison is also given of our classical Monte Carlo results with exact diagonalization results in small triangular quantum clusters, providing further support for our thermal description of this compound. © 2009 The American Physical Society.

Más información

Título según WOS: Metastable states in the triangular-lattice Ising model studied by Monte Carlo simulations: Application to the spin-chain compound Ca3Co2O6
Título según SCOPUS: Metastable states in the triangular-lattice Ising model studied by Monte Carlo simulations: Application to the spin-chain compound Ca3 Co2 O6
Título de la Revista: PHYSICAL REVIEW B
Volumen: 79
Número: 18
Editorial: American Physical Society
Fecha de publicación: 2009
Idioma: English
URL: http://link.aps.org/doi/10.1103/PhysRevB.79.184422
DOI:

10.1103/PhysRevB.79.184422

Notas: ISI, SCOPUS