Size-independent spin switching field using synthetic antiferromagnets

Abstract

The arrays of the synthetic antiferromagnetic (SyAF) patterned bits consisting of Co90Fe10 (t1nm)/Ru (d nm)/Co90Fe10 (t2 nm) were successfully fabricated with micron to submicron sizes and different aspect ratios. Magnetization switching field Hsw and magnetic domain structure were investigated using magneto-optical Kerr effect and magnetic force microscopy (MFM), respectively. It was demonstrated that the strongly AF-coupled SyAF with aspect ratio k=1 creates size-independent Hsw down to submicron sizes fabricated, which is understood by zero demagnetization field for k=1 and single domain structure, observed by MFM. The size-independent switching field demonstrates the predominance of the SyAF for spintronics devices, requiring a low switching field and stabilized single domain structure for small bit sizes such as ultrahigh density magnetic random access memories and spin transistors.