Ion irradiation and implantation modifications of magneto-ionically induced exchange bias in Gd/NiCoO

Abstract

Magneto-ionic control of magnetic properties through ionic migration has shown promise in enabling new functionalities in energy-efficient spintronic devices. In this work, we demonstrate the effect of helium ion irradiation and oxygen implantation on magneto-ionically induced exchange bias effect in Gd/Ni${}_{0.33}$Co${}_{0.67}$O heterostructures. Irradiation using $H{e}^{+}$ leads to an expansion of the Ni${}_{0.33}$Co${}_{0.67}$O lattice due to strain relaxation. At low He+ fluence ($\le$ 2$\times$10${}^{14}$ ions cm${}^{-2}$), the redox-induced interfacial magnetic moment initially increases, owing to enhanced oxygen migration. At higher fluence, the exchange bias is suppressed due to reduction of pinned uncompensated interfacial Ni${}_{0.33}$Co${}_{0.67}$O spins. For oxygen implanted samples, an initial lattice expansion below a dose of 5$\times$10${}^{15}$ cm${}^{-2}$ is subsequently dominated at higher dose by a lattice contraction and phase segregation into NiO and CoO-rich phases, which in turn alters the exchange bias. These results highlight the possibility of ion irradiation and implantation as an effective means to tailor magneto-ionic effects.

20 pages, 4 figures

References in corpus (6)

• Magneto-ionic Control of Interfacial Magnetism
• Reversible control of Co magnetism by voltage induced oxidation
• Asymmetric Reversal in Inhomogeneous Magnetic Heterostructures
• Electrically Enhanced Exchange Bias via Solid State Magneto-Ionics
• Tuning Perpendicular Anisotropy Gradient in Co/Pd Multilayers by Ion Irradiation
• Interfacial-Redox-Induced Tuning of Superconductivity in YBa${}_2$Cu${}_3$O${}_{7-\delta }$