Spin reorientation in Tm/sub 2.14/Bi/sub 0.80/Pb/sub 0.06/ Fe/sub 3.1/Ga/sub 1.9/O/sub 12/ thin films

A single-crystal garnet thin film has been found to undergo a continuous reorientation of its easy direction of magnetization from in-plane to perpendicular to the plane over a temperature range of 100 K to 125 K. The temperature range was determined by following the temperature dependence of the remanent magnetization in zero magnetic field. The existence of a significant uniaxial anisotropy is evidenced by the inability to saturate the sample in both directions at 3 kG. A model has been proposed that explains the phenomena by considering the existence of a uniaxial anisotropy energy to fourth order. The model successfully predicts a second-order phase transition taking place for the appropriate temperature dependence of the anisotropy constants.<
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