Characterization of Fe-Ni-Pt(Zr) magnetron deposited thin films subjected to low-temperature annealing

Abstract

Creation of FeNi-based hard magnetic materials for a high-density recording media depends on many factors including chemistry, synthesis conditions and subsequent heat-treatments. In particular Fe-Ni thin films can be fabricated by sputtering, molecular beam epitaxy and electrodeposition. The highest values of anisotropy constant are obtained for ordered tP4/L10-FeNi compound. From the viewpoint of practical use, a challenging task is to propose the relevant technological schemes for fabrication of this compound. This work is devoted to a study of three types of materials produced by radio frequency magnetron sputtering: layered Fe/(Ni,Pt) crystalline samples deposited at room temperature and subsequently annealed, homogeneous crystalline Fe(Ni,Pt) samples deposited at elevated substrate temperature and amorphous Fe-Ni-Pt-Zr samples deposited at room temperature which were further crystallized on heating. The phase composition of the sample was studied by X-ray diffractometry while the obtained nanostructure was observed by transmission electron microscopy. Thermally crystallized Fe-Ni-Pt-Zr samples exhibited the best combination of magnetic properties among the deposited films though partial oxidation of the samples took place on sputtering and annealing. Chemical composition and microstructure features, namely grain structure and defects in the Fe(Ni,Pt) samples are proposed to be main reasons responsible for the observed magnetic properties.