Low Power Spin Switching Technique: Recent Research Progress and a Proposal of Strong Antiparalelly Coupled Elements

摘要

Magnetic domain structures and magnetic switching properties in synthetic antiferromagnetic (SyAF) patterned bits consisting of Co_(90)Fe_(10)/Ru/Co_(9)Fe_(10) were studied to achieve a stabilized single domain structure and a low switching field. These elements, having widths from 0.2 to 100 (mu)m and aspect ratios from 1 to 8, were fabricated using electron beam lithography and an argon ion milling technique. Magnetic domain structure and magnetization switching field were investigated using magnetic force microscopy (MFM) and magnetooptical Kerr effect, respectively. The MFM image of these bits exhibits a single domain structure even for a small aspect ratio of k = 1. we demonstrated that the switching field is independent of the element width for bits with a strong exchange coupling field between the top and bottom ferromagnetic layers. Magnetic tunnel junctions (MTJs) with an SyAF free layer were also fabricated to study spin switching behavior. we found that MTJs with an SyAF free layer maintain a high remanence value in addition to a size-independent switching field for k = 1.