Magnetic properties and microstructure studies of Sm-Fe magnetic thin films

Binary SmxFe100-x(2<x<12) thin films were made by rf sputtering of the target onto preheated quartz glass substrates. Structural characterization, magnetic measurement, and microstructure observation were carried nut by x-ray diffractometer, vibrating sample magnetometer scanning electron microscope, and transmission electron microscope (TEM), respectively. Directly crystallized films were synthesized at substrate temperature higher than 400 degrees C and the main phase of the films is the ThMn12-type tetragonal phase with lattice parameters a = 8.65 Angstrom and c = 4.78 Angstrom. Films have the predominant [111] and [001] crystallographic texture when the substrate temperature is lower and higher than 600 degrees C, respectively. The perpendicular magnetization measured under the applied held of 22 kOe is about 30% higher than the saturation magnetization of bulk SmFe11Ti. Coercivities of about 4.0 kOe can be obtained in the substrate temperature range between 430 and 550 degrees C with grain size of 0.2-0.3 mu m. Cross-sectional TEM microstructure observations show significant columnar structures in the films. The [001] texture formed in the films is also clearly reflected by the planar and cross-sectional TEM diffraction patterns. (C) 1997 American Institute of Physics.