Search for: All records

Unidirectional spin Hall magnetoresistance (USMR) is a magnetoresistance effect with potential applications to read two-terminal spin–orbit-torque (SOT) devices directly. In this work, we observed a large USMR value (up to 0.7 × 10 −11 per A/cm 2 , 50% larger than reported values from heavy metals) in sputtered amorphous PtSn 4 /CoFeB bilayers. Ta/CoFeB bilayers with interfacial MgO insertion layers are deposited as control samples. The control experiments show that increasing the interfacial resistance can increase the USMR value, which is the case in PtSn 4 /CoFeB bilayers. The observation of a large USMR value in an amorphous spin–orbit-torque material has provided an alternative pathway for USMR application in two-terminal SOT devices. 

The microstructure of FeCuB ribbons (∼20 μm thick) was modified to fabricate α′′-Fe 16 N 2 at a temperature as low as 160 °C. The ribbon samples were heat treated first at a temperature reaching 930 °C and then quenched down to room temperature. During the heat treatment, ribbon samples were oxidized, and hydrogen reduction was then conducted to remove the oxygen from the ribbon samples. The reduced ribbon samples had a porous structure, which improved the nitrogen diffusion efficiency and decreased the fabrication temperature of α′′-Fe 16 N 2 down to 160 °C. It was demonstrated that the techniques for microstructure control in this method including oxidation and reduction helped obtain the α′′-Fe 16 N 2 phase with high coercivity, thus manifesting this could be a promising technique for low-temperature nitridation on ribbons in general.