Magnetic and Structural Properties of Ferromagnetic GeMnTe Layers
Ferromagnetic Ge1−xMnxTe thin films with x≤0.19 were deposited on (111) oriented BaF2 monocrystals using molecular beam epitaxy technique. X-ray diffraction carried out at high temperatures for samples with x≤0.05 revealed ferroelectric transition from rock-salt to rhombohedral structure at T=625–675 K. The magnetic properties investigated with SQUID magnetometry and ferromagnetic resonance technique exhibit an easy magnetization direction normal to the plane in as grown samples. We attribute this finding to lattice strain due to mismatch of thermal expansion coefficients or to the crystalline stress related to inhomogeneous distribution of Mn ions in the sample volume. Thermal treatment changes the easy axis into in-plane direction which can be associated with distinct improvement of the structural properties.
KeywordsEasy Axis Rhombohedral Structure Easy Magnetization Axis Ferromagnetic Transition Ferroelectric Transition
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