Estudo do comportamento anômalo da susceptibilidade magnética em filmes finos

Abstract

In this work we will study the magnetic properties like magnetization and susceptibility of then film using the Heisenberg model for a simple cubic lattice. We will use the differential operator technique along with the theory of effective field. These system are constituted of surface (layer) formed for atoms whose respective positions define the type of exchange interaction: Js for delimited surface and J for the interior of the material (bulk). Initially we will describe briefly the theory proposed to explain the nature of the magnetic phenomena and present some results already obtain in the area. We will present the theory of effective field and the differential operator technique and tool used in our work for the study of ferromagnetic (F) and antiferromagnetic (AF) materials, within Heisenberg model. The effects of exchange interaction J and Js, external magnetic filed H and number of layer L present in our thin magnetic films have been observed through the numerical solution of the respective equations for magnetizations an susceptibility. The observations help in the phenomenal like the anomalous behavior of total susceptibility, a possible quantum phase transition for the staggered magnetization of AF material.