We investigate the in-plane magnetic anisotropy in La0.67Sr0.33MnO3 thin films grown on SrTiO3 (001) substrate using angular dependent room temperature Vectorial Magneto-Optical Kerr Magnetometry. ...The experimental data reveals that the magnetic anisotropy symmetry landscape significantly changes depending upon the strain and thickness. At low film thickness (12 and 25 nm) the dominant uniaxial anisotropy is due to interface effects, step edges due to mis-cut angle of SrTiO3 substrate. At intermediate thickness, the magnetic anisotropy presents a competition between magnetocrystalline (biaxial) and substrate step induced (uniaxial) anisotropy. Depending upon their relative strengths, a profound biaxial or uniaxial or mixed anisotropy is favoured. Above the critical thickness, magnetocrystalline anisotropy dominates all other effects and shows a biaxial anisotropy.
The magnetization reversal of La0.7Sr0.3MnO3 (LSMO) epitaxial films deposited on 10 vicinal SrTiO3(001) substrates has been investigated at room temperature by using longitudinal magneto-optical Kerr ...microscopy. In the case when the magnetic field is applied parallel to the substrate steps, magnetization reversal proceeds first by the nucleation of magnetic domains with well-defined magnetic domain walls (DWs) oriented parallel to the step direction and then by DW propagation. No magnetic domains are found in the case when the magnetic field is applied perpendicular to the steps, in which case magnetization reversal proceeds by coherent rotation. Our results provide a direct visualization of the step-induced uniaxial magnetic anisotropy in half-metallic systems and for LSMO thickness up to 70 nm.
La0.7Sr0.3MnO3 (LSMO) thin films (with a thickness of 10, 20, 60, 75, and 100 nm) were grown on SrTiO3 (STO)‐buffered silicon (001) substrates by reactive molecular‐beam epitaxy. X‐ray diffraction ...(XRD) revealed the heterostructures to be fully epitaxial with orientation relationship (001) LSMO || (001) STO || (001) Si and 100 LSMO || 100 STO || 110 Si. Root mean square roughness was about 0.5 nm as measured by atomic force microscopy (AFM) for films of 10–75 nm thicknesses, and about 1 nm for the 100 nm thick LSMO film. Normalized Hooge parameters in the (0.95 ± 0.25) × 10−30–(3.41 ± 0.71) × 10−30 m3 range were measured at 300 K, which are comparable to the noise level typically measured in the best LSMO films on (001) STO substrates. Overall these very low noise LSMO films with thicknesses in the 10–100 nm range grown on STO/Si showed properties rivaling those of LSMO films deposited on (001) STO single crystal substrates, thus demonstrating their potential use for LSMO‐based devices on silicon substrates.
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