Observation of Spin Hall Magnetoresistance on Quasi-antiferromagnetic Layer

摘要

Recently spin Hall magnetoresistance (SMR) of antiferromagnet (AFM) has been attracting attention, whereas we fabricated a Quasi-antiferromagnet (Quasi-AFM) which is an intermediate state between ferromagnet (FM) and AFM. In this report, we investigate SMR of a Quasi-AFM.Samples 1 and 2were sputtered on thermally-oxidized Si substrates and annealed in a field of 0.42 [T] at 270 [°C] for 1 [h] as shown in Figure 1. The magnetization of the lower CoFe is pinned by IrMn, and the upper and lower CoFe are magnetically coupled through Fe-O at an angle of +/-90 degrees, resulting that the upper CoFe becomes a Quasi-AFM. Although Sample 1 is expected to show SMR owing to a heavy metal Pt layer on a Quasi-AFM, Sample 2 cannot exhibit SMR on Quasi-AFM. Magnetoresistance was measured in a magnetic field from -0.3 [T] to 0.3 [T].