Ionic switching between supermagnetic states

Sumaiyatul Ahsan; Yin-Ju Yen; Andrew H. Comstock; Tanya A. Balandin; Jason D. Azoulay; Jamie H. Warner; Dario A. Arena; Faisal M. Alamgir

arXiv · 2610.23829

Ionic switching between supermagnetic states

Sumaiyatul Ahsan·Yin-Ju Yen·Andrew H. Comstock·Tanya A. Balandin·Jason D. Azoulay·Jamie H. Warner·Dario A. Arena·Faisal M. Alamgir

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Abstract

Supermagnetic states are typically set during synthesis. Changing and retaining these states requires sustained external stimulus. Without resynthesis or continued stimulus, we show, for the first time, a reversible magneto-ionic switching between superferromagnetic (SFM) and superspin-glass (SSG) states using room-temperature Li-ion transport. We utilize the incomplete lithiation of NiO into nanoscale Ni and Li2O to switch between the states. Lithiation generates a fragmented nano-Ni network that strengthens dipolar interactions and promotes SFM order with stronger memory and higher room-temperature moments. Delithiation partially regenerates NiO and drives the system into an SSG state with higher low-temperature coercivity and sharper temperature-selective memory. The interconversion between SFM and SSG persists at all measured subsequent lithiation-delithiation cycles, creating a general framework for supermagnetic switching.

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Sumaiyatul Ahsan, Yin-Ju Yen, Andrew H. Comstock, Tanya A. Balandin, Jason D. Azoulay, Jamie H. Warner, Dario A. Arena, Faisal M. Alamgir. 2026-10-16. Ionic switching between supermagnetic states. https://arxiv.org/abs/2610.23829

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