Calculation of hysteresis loops in face-centered cubic thin films

Abstract

A total energy equation for a single-crystalline face-centered cubic thin film with its close-packed (111) plane parallel to the film plane is used to calculate in-plane and out-of-plane hysteresis loops at various values of the cubic magnetocrystalline anisotropy constant (K(1)). In-plane loops show that the easy and hard axes are the < 112 > and < 110 > directions, respectively, and that the coercivities, which are nearly independent of the sign of K(1), are quite low over the K(1) values due to the small variation of the magnetocrystalline anisotropy energy during the field sweep. The out-of-plane loops are similarly shaped to those of typical thin films, except for the appearance of a small hysteresis loop near the origin, which is attributed to an irreversible magnetization jump from one easy axis to another in the (111) plane. The magnetic parameters such as K(1) are estimated by comparing the theoretical results for in-plane and out-of-plane hysteresis loops with the experimental results measured for an epitaxial Co thin film. The value of K(1) is estimated to be -1.2 x 10(6) erg/cm(3), which is significantly higher than that of -6 x 10(5) erg/cm(3) for bulk Co, but is in good agreement with the values of -1.3 to -1.6 x 10(6) erg/cm(3) reported for Co thin films. (C) 2011 Elsevier B.V. All rights reserved.