Controlling magnetization switching and DC transport properties of magnetic tunnel junctions by mircowave injection

Abstract

Searching new approaches to combine spintronic devices and microwave applications is a fascinating topic. On one hand, the application of spintronic devices opens new roads to generate and detect microwave in wide frequency range, on the other hand, applying/injection microwave also modulates the spintronic devices properties. In this report, we present our recent work on effects of MW injection on the switching properties of magnetic tunneling junctions (MTJs). Magnetic tunneling junction is a promising device cell choice for spintronic applications, such as magnetic sensors, nonvolatile magnetic random access memories, and magnetic logical. As the MTJ cell size approaches to nanoscale, magnetic materials with large magnetic anisotropy are usually adopted as MTJ magnetic electrodes to keep the thermal stability. This usually inevitably increases magnetization switching field or spin transfer torque switching current density. Therefore, searching methods to assist MTJ magnetization switching becomes important for practical applications. Here, we show that directly injecting microwave current into MTJ and taking advantage of microwave current induced spin transfer torque (STT) effect can assist magnetization switching effectively. Since microwave current rather than MW magnetic field is utilized, it enables us to control the switching assistance electrically and eliminates cross-talking between neighboring cells.