The Spin Reorientation Transition and Phase Diagram of Ultrathin Ferromagnetic Films

Date
Authors
Carubelli, Marianela
Billoni, Orlando V.
Pighin, Santiago
Cannas, Sergio A.
Stariolo, Daniel A.
Tamarit, Francisco A.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
We show results from Monte Carlo simulations of a two dimensional Heisenberg model for ultrathin films with perpendicular anisotropy. A complete phase diagram is obtained as a function of anisotropy and temperature, spanning a wide range of behavior. We discuss our results in relation with experimental findings in different ultrathin films. We observe and characterize a line of Spin Reorientation Transitions . This transition from out of plane stripe order to in plane ferromagnetic order presents a paramagnetic gap in between in a finite region in parameter space, as reported in experiments. For large anisotropies direct transitions from a low temperature stripe phase to a paramagnetic or tetragonal phase with dominant perpendicular magnetization is observed, also in agreement with experiments. We also show the phase diagram for a system without exchange, i.e. with pure dipolar and anisotropy interactions. It shows a similar behavior to the ferromagnetic case with antiferromagnetic instead of stripe phases at low temperatures. A Spin Reorientation Transition is also found in this case.
Comment: 9 pages, 13 figures
Keywords
Condensed Matter - Disordered Systems and Neural Networks, Condensed Matter - Statistical Mechanics
Citation
Collections