Spin-orbit-torque MRAM: from uniaxial to unidirectional switching

Abstract

With ultra-fast writing capacity and high reliability, the spin-orbit torque is regarded as a promising alternative to fabricate next-generation magnetic random access memory. However, the three-terminal setup can be challenging when scaling down the cell size. In particular, the thermal stability is an important issue. Here we demonstrate that the current-pulse-induced perpendicular exchange bias can significantly relieve the concern of thermal stability. The switching of the exchange bias direction is induced by the spin-orbit torque when passing current pulses through the Pt/Co system with an inserted IrMn antiferromagnetic layer. Manipulating the current-pulse-induced exchange bias, spin-orbit-torque switching at zero field between states with unidirectional anisotropy is achieved and the thermal agitation of the magnetic moment is strongly suppressed. The spin-orbit torque mechanism provides an innovative method to generate and to control the exchange bias by electrical means, which enables us to realize the new switching mechanism of highly stable perpendicular memory cells.

References in corpus (11)

• Antiferromagnetic spintronics
• Magnetic switching by spin torque from the spin Hall effect
• Spin Transfer Torques
• Spin Torque Ferromagnetic Resonance Induced by the Spin Hall Effect
• Symmetry and magnitude of spin-orbit torques in ferromagnetic heterostructures
• Switching of perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields
• Magnetization switching by spin-orbit torque in an antiferromagnet/ferromagnet bilayer system
• Field-free magnetization reversal by spin-Hall effect and exchange bias
• All electrical manipulation of magnetization dynamics in a ferromagnet by antiferromagnets with anisotropic spin Hall effects
• Current induced torques in structures with ultra-thin IrMn antiferromagnet
• Controlled enhancement or suppression of exchange biasing using impurity $\delta$-layers

Cited by in corpus (3)

• FMR-related phenomena in spintronic devices
• Survey on STT-MRAM Testing: Failure Mechanisms, Fault Models, and Tests
• Voltage Control of Perpendicular Exchange Bias in Multiferroic Heterostructures