Thermal stability for domain wall mediated magnetization reversal in perpendicular STT MRAM cells with W insertion layers

Abstract

We present an analytical model for calculating energy barrier for the magnetic field-driven domain wall-mediated magnetization reversal of a magneto-resistive random access memory (MRAM) cell and apply it to study thermal stability factor $\Delta$ for various thicknesses of W layers inserted into the free layer (FL) as a function of the cell size and temperature. We find that, by increasing W thickness, the effective perpendicular magnetic anisotropy (PMA) energy density of the FL film monotonically increases, but at the same time, $\Delta$ of the cell mainly decreases. Our analysis shows that, in addition to saturation magnetization $M_s$ and exchange stiffness constant $A_{\mathrm{ex}}$ of the FL film, the parameter that quantifies the $\Delta$ of the cell is its coercive field $H_c$, rather than the net PMA field $H_k$ of the FL film comprising the cell.

arXiv comment8 pages, supplementary material included

References in corpus (5)

• Domain structure in CoFeB thin films with perpendicular magnetic anisotropy
• Magnetization switching in a Heisenberg model for small ferromagnetic particles
• Thermally nucleated magnetic reversal in CoFeB/MgO nanodots
• Ultrathin perpendicular free layers for lowering the switching current in STT-MRAM
• Reduced Exchange Interactions in Magnetic Tunnel Junction Free Layers with Insertion Layers

Cited by in corpus (1)

• Ultrathin perpendicular free layers for lowering the switching current in STT-MRAM