A MONTE CARLO SIMULATION OF MAGNETIC ORDERING IN ISING FERRITES OF FORMULA 5Fe₂O₃.3Y₂O₃WITH GARNET STRUCTURE

Abstract

The magnetic properties simulation of extended networks containing quantum spins, by original FORTRAN code "MCIsing", is presented. The computer code is based on Ising model and uses Monte Carlo-Metropolis (MCM) algorithm. The results of magnetic Monte Carlo studies on a garnet type lattice, Ising model ferrimagnet, provide insights into the exchange interactions involved in the Ferrites of Formula 5 Fe 2 O 3.3 Y 2 O 3 with Garnet Structure.

Monte Carlo simulation of magnetic ordering in the Gd3Fe5O12 Ising ferrite with garnet structure

“…For each site, of type r(r=a, d or c) and a given order number r (1prp512 or 1728, respectively, for 8 or 27 full cubic elementary cell (FCEC) [10,11,26]), having the system in general configuration, ascribed by the set S z of all-site spin projections, one may assign a site Ising energy, as follows:…”

“…In order to avoid the over-parameterization, we systematically considered parameter transferability from previous results [5,17,23] imposing also J cc =0. For the Y 3 F 5 O 12 case, J ad , J aa and J dd have been computed [11] from comparison between simulated and experimental data [24]. Since amongst the rare-earth iron garnets T c is approximately constant, it can be assumed that the Fe III -Fe III interaction exchange parameter J ad is dominant; thus, the value obtained from the Y 3 Fe 5 O 12 case remains constant for Gd 3 Fe 5 O 12 and for all the REIGs.…”

“…For Gd 3 Fe 5 O 12 case, parameters P 1 and P 2 were kept frozen at the respective 0.05 and 0.11 values [11], obtained from comparison between simulated and experimental data [24].…”

“…One of us (NS) developed a FORTRAN computer code, and initiated a systematic investigation of related prototype systems in a series of papers [10,11,26]. The Ising Spin model is appropriate for the systems with magnetic anisotropy, as the networks behaving as magnets implicitly are.…”

“…The results of MC simulations on the Ising ferrimagnet represented by the Gd 3 Fe 5 O 12 case (GdIG) are initiated starting from the parameters of the iron sublattice, taken transferable from previous analyses of the YIG system [10,11]. The YIG system represents the diamagnetic reference for the trivalent ions, adding here the new quantum spin of Gd (III) as a new step in the systematization of magnetism in REIG complex lattices.…”