R&D: Detection of In-Plane Magnetized Grains with Magnetoresistive Head

IEEE Magnetics Letters has published an article written by Yifei Chen, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA, and R. H. Victora,Deparment of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.

Abstract: “MgO is an important component in heat-assisted magnetic recording (HAMR) media, serving as an excellent seed layer for perpendicular orientation of FePt grains. However, it is difficult to detect the in-plane magnetic grains caused by the MgO boundaries. This work uses micromagnetic simulation to study the detection of longitudinally magnetized grains in FePt-based HAMR media using a novel 45∘ magnetoresistive (MR) read head design. By leveraging the reduced in-plane anisotropy of FePt grains and the magnetostatic field generated by adjacent tracks, an asymmetric magnetization distribution is induced along the cross-track direction. This asymmetry facilitates the detection of in-plane magnetization components using playback signals obtained from micromagnetic simulations. The proposed method effectively identifies noise sources, thus providing a cost-efficient alternative to other experimental techniques.“