Yukiharu Takeda

Characterization of magnetic components in the diluted magnetic semiconductor Zn1-xCoxO by x-ray magnetic circular dichroism

We report on the results of x-ray absorption (XAS), x-ray magnetic circular dichroism (XMCD), and photoemission experiments on {\it n}-type Zn

Electronic structure and magnetism of the diluted magnetic semiconductor Fe-doped ZnO nanoparticles

_{1-x}

Unveiling the impurity band induced ferromagnetism in the magnetic semiconductor (Ga,Mn)As

Co

Performance upgrade in the JAEA actinide science beamline BL23SU at SPring-8 with a new twin-helical undulator

_x

Spin and orbital magnetic moments of molecular beam epitaxy γ′-Fe4N films on LaAlO3(001) and MgO(001) substrates by x-ray magnetic circular dichroism

O (

Enhanced ferromagnetic moment in Co-doped BiFeO3 thin films studied by soft x-ray circular dichroism

x=0.05

Ferromagnetism in ZnO co-doped with Mn and N studied by soft x-ray magnetic circular dichroism

) thin film, which shows ferromagnetism at room temperature. The XMCD spectra show a multiplet structure, characteristic of the Co

4f-derived Fermi surfaces of CeRu2(Si1-xGex)2 near the quantum critical point: resonant soft-X-ray ARPES study.

^{2+}

X-dependent electronic structure of YbXCu4 (X = In, Cd, Mg) investigated by high-resolution photoemission spectroscopy

ion tetrahedrally coordinated by oxygen, suggesting that the ferromagnetism comes from Co ions substituting the Zn site in ZnO. The magnetic field and temperature dependences of the XMCD spectra imply that the non-ferromagnetic Co ions are strongly coupled antiferromagnetically with each other.

Electronic configuration of Mn ions in the π-d molecular ferromagnet β-Mn phthalocyanine studied by soft X-ray magnetic circular dichroism

We have studied the electronic structure of Fe-doped ZnO nanoparticles, which have been reported to show ferromagnetism at room temperature, by x-ray photoemission spectroscopy, resonant photoemission spectroscopy, x-ray absorption spectroscopy, and x-ray magnetic circular dichroism (XMCD). From the experimental and cluster-model calculation results, we find that Fe atoms are predominantly in the Fe3+ ionic state with mixture of a small amount of Fe2+ and that Fe3+ ions are dominant in the surface region of the nanoparticles. It is shown that the room temperature ferromagnetism in the Fe-doped ZnO nanoparticles primarily originated from the antiferromagnetic coupling between unequal amounts of Fe3+ ions occupying two sets of nonequivalent positions in the region of the XMCD probing depth of ∼2–3 nm.