Skew scattering dominated anomalous Hall effect in Cox(MgO)100-x granular thin films

Qiang Zhang, Yan Wen, Yuelei Zhao, Peng Li, Xin He, Junli Zhang, Yao He, Yong Peng, Ronghai Yu, Xixiang Zhang

Research output: Contribution to journalArticle

Abstract

We investigated the mechanism(s) of the anomalous Hall effect (AHE) in magnetic granular materials by fabricating 100 nm-thick thin films of Cox(MgO)100-x with a Co volume fraction of 34 x 100 using co-sputtering at room temperature. We measured the temperature dependence of longitudinal resistivity () and anomalous Hall resistivity () from 5 K to 300 K in all samples. We found that when x decreases from 100 to 34, the values of and respectively increased by about four and three orders in magnitude. By linearly fitting the data, obtained at 5 K, of anomalous Hall coefficient () and of to , we found that our results perfectly fell on a straight line with a slope of 0.97 ± 0.02. This fitting value of in clearly suggests that skew scattering dominated the AHE in this granular system. To explore the effect of the scattering on the AHE, we performed the same measurements on annealed samples. We found that although both and significantly reduced after annealing, the correlation between them was almost the same, which was confirmed by the fitted value, = 0.99 ± 0.03. These data strongly suggest that the AHE originates from the skew scattering in Co-MgO granular thin films no matter how strong the scattering of electrons by the interfaces and defects is. This observation may be of importance to the development of spintronic devices based on MgO.

Original languageEnglish (US)
Article number415802
JournalJournal of Physics Condensed Matter
Volume29
Issue number41
DOIs
StatePublished - Sep 4 2017

Keywords

  • anomalous Hall effect
  • ferromagnetism
  • granular thin films
  • skew scattering

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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    Zhang, Q., Wen, Y., Zhao, Y., Li, P., He, X., Zhang, J., He, Y., Peng, Y., Yu, R., & Zhang, X. (2017). Skew scattering dominated anomalous Hall effect in Cox(MgO)100-x granular thin films. Journal of Physics Condensed Matter, 29(41), [415802]. https://doi.org/10.1088/1361-648X/aa8315