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Magnetic Properties of Co/Ni Multilayers and their use in STT-RAM

The growing need to store digital information has led to the surge of finding alternative storage devices to replace the existing conventional memory technologies. Spin-transfer torque random-access memory (STT-RAM) is a new type of solid-state memory that uses electrical currents to read and write data that are stored on magnetic moment of electrons. It has unlimited endurance, excellent scalability and low power consumption. However, one of the major challenges for implementing STT-RAM is its high current to switch the magnetization. We propose a unique design of nano-pillars for STT-RAM devices consisting solely of Co/Ni multilayers that is intended to reduce the current needed to reorient the magnetization. I will present and discuss the optimization of magnetization, exchange coupling, magnetic anisotropy and damping of the multilayer structures by varying individual layer thickness, structure design and deposition parameters, which are desirable for low critical current.  Additionally, I will describe modeling performed to understand the origin of perpendicular magnetic anisotropy in Co/Ni multilayers.   The modeling takes into account the contributions from the magnetoelastic anisotropy due to the strain, the magnetocrystalline anisotropy, the roughness induced anisotropies, and the inter-diffusion of seed layer in the Co/Ni multilayers.

Monika Arora
Department of Physics, Simon Fraser University

Created April 4, 2017, Updated October 1, 2018