Patterned nanoring magnetic tunnel junctions

Abstract

Patterned nanoring (NR) magnetic tunnel junctions (MTJs) with outer diameters between 100 and 400 nm and narrow ring widths between 25 and 30 nm were fabricated. The NR structure consists of CoFeB electrodes and Al-oxide barrier. The tunneling magnetoresistance (TMR) ratio in the range of 20%-50% for the NR-MTJs with the resistance-area product lower than 50 μ m2 were observed at room temperature. These NR-MTJs allow current-induced magnetization switching with a low switching current density of around 9× 106 A cm2. Due to the small stray field and high TMR ratio, NR-MTJs offer superior prospects for very high density magnetic random access memory, recording medium, and other spintronic devices. © 2007 American Institute of Physics.