title: Observation of perpendicular exchange bias in an Ir-doped Fe2O3/Co ultrathin film system.
abstract: In this work, we investigated the temperature dependence of interface exchange coupling in an Ir-doped Fe2O3/Co system with variations in the Ir-Fe2O3thickness. Low-temperature perpendicular exchange bias was observed in the samples with an Ir-Fe2O3thickness of 5 nm or less, when it cooled from 360 K in an external magnetic field of 1 T perpendicular to the sample surface. For 5 nm-thick Ir-Fe2O3, a maximum exchange bias value of 1200 Oe was obtained at 200 K. This is the first report on perpendicular exchange bias of an Fe2O3thin film coupled with a ferromagnet. Enhancements to the Morin temperature and the magnetic anisotropy of Fe2O3caused by lattice strain, Ir doping, and the finite-size scaling effect, as well as the high quality (good crystal orientation, small roughness, etc.) of the Fe2O3film fabricated by our process, are considered to be mostly responsible for the perpendicular exchange bias obtained.
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-0845, Japan. nozaki@ecei.tohoku.ac.jp sahashi@ecei.tohoku.ac.jp.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-4621-8887
authors.initials: S
authors.lastname: Ye
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-0845, Japan. nozaki@ecei.tohoku.ac.jp sahashi@ecei.tohoku.ac.jp.
authors.forename: S P
authors.initials: SP
authors.lastname: Pati
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-0845, Japan. nozaki@ecei.tohoku.ac.jp sahashi@ecei.tohoku.ac.jp.
authors.forename: Y
authors.initials: Y
authors.lastname: Shiokawa
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-0845, Japan. nozaki@ecei.tohoku.ac.jp sahashi@ecei.tohoku.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Al-Mahdawi
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-0845, Japan. nozaki@ecei.tohoku.ac.jp sahashi@ecei.tohoku.ac.jp.
authors.forename: T
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-0845, Japan. nozaki@ecei.tohoku.ac.jp sahashi@ecei.tohoku.ac.jp and ImPACT Program, Japan Science and Technology Agency, Tokyo 102-0076, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sahashi