Observation of large low-field magnetoresistance in spinel cobaltite: A new half-metal

Abstract
Low-field magnetoresistance is an effective and energy-saving way to use half-metallic materials in magnetic reading heads and magnetic random access memory. Common spin-polarized materials with low field magnetoresistance effect are perovskite-type manganese, cobalt, and molybdenum oxides. In this study, we report a new type of spinel cobaltite materials, self-assembled nanocrystalline NiCo2O4, which shows large low field magnetoresistance as large as –19.1% at 0.5 T and –50% at 9 T (2 K). The large low field magnetoresistance is attributed to the fast magnetization rotation of the core nanocrystals. The surface spin-glass is responsible for the observed weak saturation of magnetoresistance under high fields. Our calculation demonstrates that the half-metallicity of NiCo2O4 comes from the hopping eg electrons within the tetrahedral Co-atoms and the octahedral Ni-atoms. The discovery of large low-field magnetoresistance in simple spinel oxide NiCo2O4, a non-perovskite oxide, leads to an extended family of low-field magnetoresistance materials. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

Citation
Observation of large low-field magnetoresistance in spinel cobaltite: A new half-metal 2016, 10 (2):190 physica status solidi (RRL) - Rapid Research Letters

Acknowledgements
This work was supported by National Natural Science Foundation of China (Grant No. 11204207) and Ph.D. Programs Foundation of Ministry of Education of the People’s Republic of China (Grant No. 20120032120074).

Publisher
Wiley

Journal
physica status solidi (RRL) - Rapid Research Letters

DOI
10.1002/pssr.201510402

Additional Links
http://doi.wiley.com/10.1002/pssr.201510402

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