Y. Saitoh

Probing bulk states of correlated electron systems by high-resolution resonance photoemission

Electron correlations are known to play an important role in determining the unusual physical properties of a variety of compounds. Such properties include high-temperature superconductivity, heavy fermion behaviour and metal-to-insulator transitions. High-resolution photoelectron spectroscopy (PES) provides a means of directly probing the electronic states (particularly those near the Fermi level) in these materials, but the short photoelectron mean free paths (⩽5 Å) associated with the low excitation energies conventionally used (⩽120 eV) make this a surface-sensitive technique. Now that high-resolution PES is possible at much higher energies, with mean free paths as long as 15 Å (ref. 6), it should become feasible to probe the bulk electronic states in these materials. Here we demonstrate the power of this technique by applying it to the cerium compounds CeRu2Si2 and CeRu2. Previous PES studies of these compounds revealed very similar spectra for the Ce 4f electronic states, yet it is expected that such states should be different owing to their differing degrees of hybridization with other valence bands. Our determination of the bulk Ce 4f electronic states of these compounds resolves these differences.

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

Mutual Experimental and Theoretical Validation of Bulk Photoemission Spectra of Sr1 xCaxVO3

_{1-x}

Direct k-space mapping of the electronic structure in an oxide-oxide interface.

Co

Electromagnetic properties and electronic structure of the iron-based layered superconductor LaFePO

_x

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

O (

Bulk 4f Electronic States of Ce-Based Heavy Fermion System Probed by High-Resolution Resonance Photoemission

x=0.05

VARIED LINE-SPACING PLANE GRATING MONOCHROMATOR FOR UNDULATOR BEAMLINE

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

Twin helical undulator beamline for soft X-ray spectroscopy at SPring-8

^{2+}

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

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.