Helium Ion Microscopy for Reduced Spin Orbit Torque Switching Currents

Abstract

Spin orbit torque driven switching is a favourable way to manipulate nanoscale magnetic objects for both memory and wireless communication devices. The critical current required to switch from one magnetic state to another depends on the geometry and the intrinsic properties of the materials used, which are difficult to control locally. Here we demonstrate how focused helium ion beam irradiation can modulate the local magnetic anisotropy of a Co thin film at the microscopic scale. Real-time in-situ characterisation using the anomalous Hall effect showed up to an order of magnitude reduction of the magnetic anisotropy under irradiation, and using this, multi-level switching is demonstrated. The result is that spin-switching current densities, down to 800 kA cm${}^{-2}$, can be achieved on predetermined areas of the film, without the need for lithography. The ability to vary critical currents spatially has implications not only for storage elements, but also neuromorphic and probabilistic computing.

Main text: 22 pages, 3 figures, 2 tables, 1 TOC graphic. Included SI: 2 pages, 2 figures

References in corpus (15)

• Spin torque switching with the giant spin Hall effect of tantalum
• Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current
• Switching of perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields
• Electric field control of deterministic current-induced magnetization switching in a hybrid ferromagnetic/ferroelectric structure
• Room temperature spin-orbit torque switching induced by a topological insulator
• Threshold current for switching of a perpendicular magnetic layer induced by spin Hall effect
• Helium Ion Microscopy
• Emission and Propagation of Multi-Dimensional Spin Waves with nanoscale wavelengths in Anisotropic Spin Textures
• Tuning a binary ferromagnet into a multi-state synapse with spin-orbit torque induced plasticity
• Deterministic magnetization switching using lateral spin-orbit torque
• Spin-Orbit-Torque Driven Propagating Spin Waves
• Thermally induced error: density limit for magnetic data storage
• Fast magneto-ionic switching of interface anisotropy using yttria-stabilized zirconia gate oxide
• Field-free perpendicular magnetization switching through domain wall motion in Pt/Co/Cr racetracks by spin orbit torques with the assistance of accompanying Joule heating effect
• Direct measurement of the magnetic anisotropy field in Mn--Ga and Mn--Co--Ga Heusler films

Cited by in corpus (4)

• Deterministic Generation and Guided Motion of Magnetic Skyrmions by Focused He${}^{+}$-Ion Irradiation
• Deterministic multi-level spin orbit torque switching using He+ microscopy patterning
• Grayscale control of local magnetic properties with direct-write laser annealing
• Mechanism of Oxygen Reduction via Chemical Affinity in NiO/SiO2 Interfaces Irradiated with keV Energy Hydrogen and Helium Ions for Heterostructure Fabrication