Evaluation of Magnetic Anisotropy via Intrinsic Spin Infusion

Abstract

Spintronics is a promising and emerging domain that exploits electronic intrinsic magnetic moment and spin degree of freedom. The spin infusion process dictates spin current density, giant magneto-resistance (GMR), and tunnel magneto-resistance (TMR) calculations. In addition, read reliability has become a critical barrier for magnetic random-access memory (MRAM) due to increased process-voltage-temperature (PVT) variations, and reduced critical switching current of MTJ and supply voltage, as process technology continues to downscale. The torque generated due to the direct injection of spin-polarized current into magnetic multilayers alters the magnetic orientation and leads to magnetic switching. In this chapter, we discuss the spin infusion process and spin-transfer torque (STT) in magnetic multilayers, and subsequently review the giant magneto-resistance (GMR) effect in crystalline perpendicular to the plane (CPP) geometry, and tunnel magneto-resistance (TMR) in MTJs. Next, the spin infusion magnetization switching (SIMS) and its effects on toggle spin torque (TST) based devices are elaborated. The advantages of TST-MRAM include superfast read and write operation, higher energy efficiency, and large TMR ratio. In this chapter, we discuss a compact physical model to examine spin infusion-based magnetization switching and examine that spin injection-based magnetization switching (SIMS) is 3x faster than traditional magnetization switching.