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arXiv · 0712.2426

The Spin Reorientation Transition and Phase Diagram of Ultrathin Ferromagnetic Films

Marianela Carubelli·Orlando V. Billoni·Santiago Pighin·Sergio A. Cannas·Daniel A. Stariolo·Francisco A. Tamarit
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Abstract

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.

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Marianela Carubelli, Orlando V. Billoni, Santiago Pighin, Sergio A. Cannas, Daniel A. Stariolo, Francisco A. Tamarit. 2007-12-14. The Spin Reorientation Transition and Phase Diagram of Ultrathin Ferromagnetic Films. https://doi.org/10.1103/physrevb.77.134417

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