Magnetic dichroism in angle-resolved hard x-ray photoemission from buried layers

Xeniya Kozina, Gerhard H. Fecher, Gregory Stryganyuk, Siham Ouardi, Benjamin Balke, Claudia Felser, Gerd Schönhense, Eiji Ikenaga, Takeharu Sugiyama, Naomi Kawamura, Motohiro Suzuki, Tomoyuki Taira, Tetsuya Uemura, Masafumi Yamamoto, Hiroaki Sukegawa, Wenhong Wang, Koichiro Inomata, and Keisuke Kobayashi

Phys. Rev. B 84, 054449 – Published 15 August 2011

Abstract

This work reports the measurement of magnetic dichroism in angular-resolved photoemission from in-plane magnetized buried thin films. The high bulk sensitivity of hard x-ray photoelectron spectroscopy (HAXPES) in combination with circularly polarized radiation enables the investigation of the magnetic properties of buried layers. HAXPES experiments with an excitation energy of 8 keV were performed on exchange-biased magnetic layers covered by thin oxide films. Two types of structures were investigated with the IrMn exchange-biasing layer either above or below the ferromagnetic layer: one with a CoFe layer on top and another with a Co $_{2}$ FeAl layer buried beneath the IrMn layer. A pronounced magnetic dichroism is found in the Co and Fe $2 p$ states of both materials. The localization of the magnetic moments at the Fe site conditioning the peculiar characteristics of the Co $_{2}$ FeAl Heusler compound, predicted to be a half-metallic ferromagnet, is revealed from the magnetic dichroism detected in the Fe $2 p$ states.