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Uniaxial magnetic anisotropy and type-x/y current-induced magnetization switching in oblique-angle-deposited Ta/Co-Fe-B/Pt and W/Co-Fe-B/Pt heterostructures

Amir Khan1,*, Shalini Sharma2, Tiago de Oliveira Schneider1, and Markus Meinert1,†

  • *Contact author: amir.khan@tu-darmstadt.de
  • †Contact author: markus.meinert@tu-darmstadt.de
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Phys. Rev. Applied 25, 044089 – Published 30 April, 2026

DOI: https://doi.org/10.1103/qkty-8dgb

Abstract

Planar current-induced magnetization switching (CIMS) driven by spin-orbit torque (SOT) requires an in-plane uniaxial magnetic anisotropy (UMA), which can be induced by oblique-angle sputter deposition of the heavy-metal underlayer in heavy-metal/ferromagnet heterostructures. To enhance the SOT efficiency, we employ trilayer heterostructures of (Ta or W)/Co-Fe-B/Pt, where the Co-Fe-B layer exhibits a UMA of 50 mT at a 2-nm thickness of Ta or W. The magnetization reversal in Hall-bar devices is detected through unidirectional spin-Hall magnetoresistance for the type-y geometry (easy-axis transverse to current) and planar Hall measurements for the type-x geometry (easy-axis parallel to current). Both configurations exhibit CIMS with submicrosecond current pulses, reaching switching-current densities as low as 2×1011A/m2 for a W (4 nm)/Co-Fe-B (1.4 nm)/Pt (2 nm) stack with a UMA of 146 mT. Macrospin simulations reproduce the type-y switching as coherent magnetization rotation, whereas the type-x devices switch at much lower currents than predicted, indicating that nucleation and domain-wall propagation dominate reversal in this geometry. Our results show that combining oblique-angle deposition with easy-axis engineering enables deterministic, field-free switching, paving the way for future low-power spintronic devices.

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Phys. Rev. Applied 25, 044089– Published 30 April, 2026
  • Received 20 October 2025
  • Revised 12 February 2026
  • Accepted 2 April 2026
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