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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 Co2FeAl layer buried beneath the IrMn layer. A pronounced magnetic dichroism is found in the Co and Fe 2p states of both materials. The localization of the magnetic moments at the Fe site conditioning the peculiar characteristics of the Co2FeAl Heusler compound, predicted to be a half-metallic ferromagnet, is revealed from the magnetic dichroism detected in the Fe 2p states. [ABSTRACT FROM AUTHOR]

The electronic band structure of thin films and superlattices made of Heusler compounds with NiTiSn and NiZr0.5Hf0.5Sn composition was studied by means of polarization dependent hard x-ray photoelectron spectroscopy. The linear dichroism allowed to distinguish the symmetry of the valence states of the different types of layered structures. The films exhibit a larger amount of "in-gap" states compared to bulk samples. It is shown that the films and superlattices grown with NiTiSn as starting layer exhibit an electronic structure close to bulk materials. [ABSTRACT FROM AUTHOR]

Abstract: Due to their exceptional thermoelectric properties Half-Heusler alloys like MNiSn (M=Ti,Zr,Hf) have moved into focus. The growth of single crystalline thin film TiNiSn and Zr0.5Hf0.5NiSn by dc magnetron sputtering is reported. Seebeck and resistivity measurements were performed and their dependence on epitaxial quality is shown. Seebeck coefficient, specific resistivity and power factor for Zr0.5Hf0.5NiSn at room temperature were measured to be 63μVK−1, 14.1μΩm and 0.28mWK−2 m−1, respectively. Multilayers of TiNiSn and Zr0.5Hf0.5NiSn are promising candidates to increase the thermoelectric figure-of-merit by decreasing thermal conductivity perpendicular to the interfaces. The epitaxial growth of multilayers containing TiNiSn and Zr0.5Hf0.5NiSn is demonstrated by measuring satellite peaks in the X-ray diffraction pattern originating from the additional symmetry perpendicular to the film surface. [Copyright &y& Elsevier]