Large tunnel magnetoresistance in Co2FeAl0.5Si0.5∕MgO∕Co2FeAl0.5Si0.5 magnetic tunnel junctions prepared on thermally oxidized Si substrates with MgO buffer

Abstract

Magnetic tunnel junctions (MTJs) using polycrystalline Co2FeAl0.5Si0.5 (CFAS) electrodes with a MgO tunnel barrier were fabricated onto thermally oxidized Si substrates. Highly (001)-oriented and B2-ordered CFAS electrodes were obtained by optimizing growth conditions and postannealing temperature. The microfabricated MTJs exhibited relatively high tunnel magnetoresistance (TMR) ratios of 125% at room temperature and 196% at 7K. The large TMR obtained using oxidized Si substrates indicates that CFAS is promising for the practical applications.