Search Results - person:"Araújo, Ijanı́lio G."

Study of the crossover from 2 to 3 dimensions in the quantum spin-12 anisotropic Heisenberg model

Araújo, Ijanı́lio G.; Ricardo de Sousa, J.; Branco, N.S. - In: Physica A: Statistical Mechanics and its Applications 305 (2002) 3, pp. 585-596

The phase diagram of the quantum spin-12 anisotropic Heisenberg antiferromagnet is studied, within a mean-field renormalization-group approach in larger clusters. The model consists of an anisotropic cubic lattice, with in-plane J and inter-plane J′=λJ interactions. The dependence of the...

Persistent link: https://www.econbiz.de/10011060412

Crossover of the antiferromagnet Heisenberg to XY model

Sousa, J. Ricardo de; Araújo, Ijanı́lio G; Plascak, J.A - In: Physica A: Statistical Mechanics and its Applications 278 (2000) 1, pp. 181-187

The criticality of the quantum anisotropic spin-12 Heisenberg antiferromagnetic model is studied by the mean-field renormalization group (MFRG) approach. The critical temperature and the thermal exponent for the ferromagnetic (F) and antiferromagnetic (AF) cases are obtained as a function of the...

Persistent link: https://www.econbiz.de/10011059256

Néel temperature and sublattice magnetiztion of a three-dimensional classical and quantum Heisenberg antiferromagnet11We would like to thank the CNPq and CAPES (Brazilian Agencies) for financial support.

Araújo, Ijanı́lio G.; Neto, J. Cabral; Sousa, J. … - In: Physica A: Statistical Mechanics and its Applications 260 (1998) 1, pp. 150-156

The effective-field theory (EFT) of a two-spin cluster is applied to study the critical behavior of a three-dimensional classical and quantum Heisenberg antiferromagnet (AF). Néel temperature (TN) and sublattice magnetization are calculated numerically and compared with the results of these...

Persistent link: https://www.econbiz.de/10011063638