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Strain and Defect-Tailored Magnetotransport in NiCo 2 O 4 Thin Films and Freestanding Membranes

Wu, Qiuchen [University of Nebraska, Lincoln, NE (United States)] (ORCID:0000000320075985)·Zhang, Yuanyuan [University of Nebraska, Lincoln, NE (United States)] (ORCID:0009000937117572)·Li, Tianlin [University of Nebraska, Lincoln, NE (United States)]·Han, Myung-Geun [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000237363281)·Hwang, Soo-Yoon [Brookhaven National Laboratory (BNL), Upton, NY (United States); Pohang University of Science and Technology (POSTECH) (Korea, Republic of)]·Nam, Yeon-Seo [Brookhaven National Laboratory (BNL), Upton, NY (United States); Pohang University of Science and Technology (POSTECH) (Korea, Republic of)]·Choi, Si-Young [Pohang University of Science and Technology (POSTECH) (Korea, Republic of)] (ORCID:000000031648142X)·Zhu, Yimei [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000216387217)·Hong, Xia [University of Nebraska, Lincoln, NE (United States)] (ORCID:0000000278735774)
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Abstract

Magnetic spinel NiCo 2 O 4 is promising for developing spintronic applications due to its high magnetic Curie temperature, high spin polarization, fast spin dynamics, and strain-tunable magnetic anisotropy, while its electronic and magnetic properties depend sensitively on epitaxial strain and disorder. Here, in this study, we use epitaxial NiCo 2 O 4 thin films and freestanding NiCo 2 O 4 membranes as model systems to reveal the complex interplay of strain and defects in determining the metallicity and magnetotransport properties of the ferrimagnetic spinel. NiCo 2 O 4 on perovskite substrates and NiCo 2 O 4 membranes exhibit insulating behaviors and spin canting, in sharp contrast to the metallic NiCo 2 O 4 films on spinel substrates that possess strong perpendicular magnetic anisotropy. Anisotropic magnetoresistance studies provide critical information about disorder-induced spin scattering and strain-induced tetragonal magnetocrystalline anisotropy, which is corroborated by comprehensive electron microscopy characterizations. Our study presents a promising venue for designing flexible magnetic memory, sensor, and spintronic applications.

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36 MATERIALS SCIENCE75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY77 NANOSCIENCE AND NANOTECHNOLOGYanisotropic magnetoresistanceanomalous Hall effectepitaxyfreestanding spinel membranesmagnetic propertiesmagnetocrystalline anisotropymembranesoxidesphase separationthin films

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Wu, Qiuchen [University of Nebraska, Lincoln, NE (United States)] (ORCID:0000000320075985), Zhang, Yuanyuan [University of Nebraska, Lincoln, NE (United States)] (ORCID:0009000937117572), Li, Tianlin [University of Nebraska, Lincoln, NE (United States)], Han, Myung-Geun [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000237363281), Hwang, Soo-Yoon [Brookhaven National Laboratory (BNL), Upton, NY (United States); Pohang University of Science and Technology (POSTECH) (Korea, Republic of)], Nam, Yeon-Seo [Brookhaven National Laboratory (BNL), Upton, NY (United States); Pohang University of Science and Technology (POSTECH) (Korea, Republic of)], Choi, Si-Young [Pohang University of Science and Technology (POSTECH) (Korea, Republic of)] (ORCID:000000031648142X), Zhu, Yimei [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000216387217), Hong, Xia [University of Nebraska, Lincoln, NE (United States)] (ORCID:0000000278735774). 2026-03-30. Strain and Defect-Tailored Magnetotransport in NiCo 2 O 4 Thin Films and Freestanding Membranes. https://doi.org/10.1021/acsnano.5c20447

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36 MATERIALS SCIENCE subject75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY subject77 NANOSCIENCE AND NANOTECHNOLOGY subjectOxides subjectThin films subjectmagnetic properties subject

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