Bulk Magnetic Properties of the Fe_(0.5)Mn_(0.1)Al_(0.4) Disordered Alloy: A Monte Carlo Study

摘要

In this work we present a simulational study of the bulk magnetic properties of the Fe_(0.5_Mn_(0.1_Al_(0.4) disordered system. The magnetization per site, specific heat and magnetic susceptibility were obtained using Monte Carlo simulation. Simulation results were performed in the framework of a random site-diluted 3D Ising model with nearest neighbor interactions, and using a single-spin-flip Metropolis dynamics for equilibration and energy minimization, from which canonical ensemble and configurational averages were computed. In the simulation, atoms were randomly distributed on a body-centered cubic lattice in order to simulate the disorder and crystalline structure as obtained in the arc-melted Fe0.5Mn0.1Al0.4 alloy treated at high temperatures for long periods of time and followed by fast quenching. Competitive Fe–Fe ferromagnetic and Fe–Mn and Mn–Mn antiferromagnetic interactions were taken into account, as well as the Al dilutor effect. We conclude that, accordingly with M?ssbauer results, the Fe_(0.5_Mn_(0.1)Al_(0.4) system exhibits a reentrant spin-glass behavior below 30 K characterized by a sharp increase of the mean hyperfine field attributed to the magnetic ordering of the Mn sublattice at these temperatures. Additionally, a ferromagnetic to paramagnetic transition at around 300 K was also evidenced.