First Principle Simulations of Fe/mgo/fe Magnetic Tunnel Junctions for Applications in Magnetoresistive Random Access Memory Based Cell Phone Architectures

Fe/MgO/Fe magnetic tunnel junctions (MTJs) have been reported to have very high tunnel magnetoresistance (TMR) ratios. In this work, we present the results of First Principle simulations of Fe/ MgO/Fe MTJs with LSDA as the exchange correlation. The I-V characteristics in the antiparallel magnetization state exhibit strong features. The bias dependence of the TMR ratio shows nearly 100% TMR ratios for bias voltages up to 1.5 Volts. The MgO thickness dependence of the tunnel resistance shows the expected exponential increase in the tunnel resistance. The write energy per bit and power consumption have been computed for a bias voltage of 0.5 Volts. The Fe/MgO/Fe MTJs are the most widely used MTJs, integrated with NMOS transistors, in the form of MTJ based Magnetoresistive Random Access Memory (MRAM) which is an advanced memory technology operating at the nano scale. MRAMs are spintronic devices.