title: Nature of magnetic coupling between Mn ions in As-grown Ga1-xMnxAs studied by X-ray magnetic circular dichroism.
abstract: The magnetic properties of as-grown Ga1-xMnxAs have been investigated by the systematic measurements of temperature and magnetic field dependent soft x-ray magnetic circular dichroism (XMCD). The intrinsic XMCD intensity at high temperatures obeys the Curie-Weiss law, but a residual spin magnetic moment appears already around 100 K, significantly above the Curie temperature (T_{C}), suggesting that short-range ferromagnetic correlations are developed above T_{C}. The present results also suggest that the antiferromagnetic interaction between the substitutional and interstitial Mn (Mn_{int}) ions exists and that the amount of the Mn_{int} affects T_{C}.
authors.affiliation: Japan Atomic Energy Agency, Synchrotron Radiation Research Center SPring-8, Sayo, Hyogo 679-5148, Japan. ytakeda@spring8.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Takeda
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Okane
authors.forename: T
authors.initials: T
authors.lastname: Ohkochi
authors.forename: J
authors.initials: J
authors.lastname: Okamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Saitoh
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: H
authors.initials: H
authors.lastname: Yamagami
authors.forename: A
authors.initials: A
authors.lastname: Fujimori
authors.forename: A
authors.initials: A
authors.lastname: Tanaka
authors.forename: J
authors.initials: J
authors.lastname: Okabayashi
authors.forename: M
authors.initials: M
authors.lastname: Oshima
authors.forename: S
authors.initials: S
authors.lastname: Ohya
authors.forename: P N
authors.initials: PN
authors.lastname: Hai
authors.forename: M
authors.initials: M
authors.lastname: Tanaka