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Updated: Aug 13, 2025

Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
Amorphous nonstoichiometric oxides with tunable room-temperature ferromagnetism and electrical transport
Qinghao Li1, Ruimin Qiao2, Apurva Mehta3
1Spintronics Institute, University of Jinan, Jinan 250022, China; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Abstract:
Material functionalities strongly depend on the stoichiometry, crystal structure, and homogeneity. Here we demonstrate an approach of amorphous nonstoichiometric inhomogeneous oxides to realize tunable ferromagnetism and electrical transport at room temperature. In order to verify the origin of the ferromagnetism, we employed a series of structural, chemical, and electronic state characterizations. Combined with electron microscopy and transport measurements, synchrotron-based grazing incident wide angle X-ray scattering, soft X-ray absorption and circular dichroism clearly reveal that the room-temperature ferromagnetism originates from the In0.23Co0.77O1-v amorphous phase with a large tunable range of oxygen vacancies. The room-temperature ferromagnetism is tunable from a high saturation magnetization of 500 emu cm-3 to below 25 emu cm-3, with the evolving electrical resistivity from 5 × 103 μΩ cm to above 2.5 × 105 μΩ cm. Inhomogeneous nano-crystallization emerges with decreasing oxygen vacancies, driving the system towards non-ferromagnetism and insulating regime. Our work unfolds the novel functionalities of amorphous nonstoichiometric inhomogeneous oxides, which opens up new opportunities for developing spintronic materials with superior magnetic and transport properties.
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