Large magnetodielectric effect based on spin-dependent charge transfer in metal-insulator type Co-(BaF2) nanogranular films

Hanae Kijima-Aoki, Yang Cao, Nobukiyo Kobayashi, Saburo Takahashi, Shigehiro Ohnuma, Hiroshi Masumoto

Research output: Contribution to journalArticlepeer-review

Abstract

Cobalt-metal-fluoride nanogranular films exhibit high electrical resistivity (ρ) and high permittivity (ϵ′) as well as high magnetic moments, making them potentially suitable for applications in low power magnetoelectronic devices at a high-frequency range. Here, we present the DC/AC magnetoelectric effect of high-ρ Cox-(BaF2)1 - x nanogranular films that are constituted of Co nanogranules of about 2 nm in diameter in an insulating BaF2 crystal. Under the application of magnetic field (H), we observed the ρ variations (Δρ/ρ0) of 2.0%-5.9% for x ranging 0.19-0.54 and the ϵ′ variations (Δϵ/ ϵ 0 ′) of 0.7%-6.0% for x ranging 0.19-0.42, respectively. These magnetically controllable ρ and ϵ′ are realized based on the spin-dependent quantum-mechanical charge transfer. The Cox-(BaF2)1 - x film for x = 0.42 possesses high ρ, while remaining in a notably high Δϵ/ ϵ 0 ′ of 6% at a megahertz frequency range. This study demonstrates a candidate of high-resistive magnetoelectric nanogranular films, which may bring prosperous applications in high-frequency magnetoelectric devices with low power consumption.

Original languageEnglish
Article number133904
JournalJournal of Applied Physics
Volume128
Issue number13
DOIs
Publication statusPublished - 2020 Oct 7

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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