Voltage induced reversible and irreversible change of magnetic coercivity in Co/ZnO heterostructure

Chuan Che Hsu, Po Chun Chang, Venkata Ramana Mudinepalli, Tsung Chun Hsieh, Fang-Yuh Lo, Wen-Chin Lin

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Abstract

In this study, the application of bias voltage to 4-8 nm Co/275 nm ZnO heterostructures changed the magnetic behavior reversibly or irreversibly, depending on the different voltage-induced mechanisms. The magnetic coercivity (Hc) monotonically decreased 20% when the small voltages of 0-8 V were applied. The Hc reduction was symmetric with the voltage polarity, and the reversibility was demonstrated by cyclically switching the bias voltage between 0 and 7 V. While a large voltage up to 40 V was applied to the Co/ZnO junction, the current heating effect became considerable and the Co-oxide was formed, as confirmed by depth-profiling X-ray photoemission spectroscopy analysis. The presence of Co-oxide in the Co films induced the irreversible reduction of the Kerr signal and Hc at room temperature. The considerable Hc enhancement at 130 K also indicates the exchange bias coupling effect from the antiferromagnetic Co-oxide.

Original languageEnglish
Article number093905
JournalJournal of Applied Physics
Volume119
Issue number9
DOIs
Publication statusPublished - 2016 Mar 7

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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