An X-Ray Diffraction-Based Method for Evaluating Inhomogeneous Ordering at the Grain Level of L1₀-FePt Media

A technique based on x-ray diffraction (XRD) is introduced to understand the variation of the grain-to-grain L1₀ ordering in FePt recording media. We classify the possible ways that the grains may be ordered into three types: homogeneous ordering, inhomogeneous ordering, and bipolar ordering. We study the possible impact of each type of ordering on the XRD spectra in terms of the relative angular positions of the FePt (001) and (002) peaks. XRD peak profile fitting is carried out to identify the grain ordering type in FePt-SiO_x thin films sputtered with in-situ heating.