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We report the unexpected evolution, with thermal and magnetic-field (H) variations, of the interrelation between the polarization P, magnetization M, and spiral wave vector Q in CoCr2O4, which has a ferrimagnetic conical-spiral magnetic order. For example, P suddenly jumps and changes its sign at the magnetic lock-in transition (T_{L}) with thermal variation, or with isothermal variation of H (without changing its direction) at T_{L}, which surprisingly occurs without change in spiral handedness (i.e., the sign of Q). The presence of multiple spiral sublattices may be behind this unusual behavior.

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The spin, in-plane and out-of-plane orbital and magnetic dipole moments of almost purely interfacial Co atoms were directly determined for Au/2-monolayer Co nanoclusters/Au(111) by angle-dependent magnetic circular x-ray dichroism (MCXD) measurements. The field- and temperature-dependent MCXD evidences a ferromagnetic(FM)-to-superparamagnetic phase transition in single-domain clusters with decreasing size. The interfacial moments are remarkably enhanced as compared with bulk values, verifying theoretical predictions. The FM clusters show strong perpendicular magnetic anisotropy, providing promise of applications for nanoscale magnetic bits.

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We investigated the magnetic structure of an orthorhombic YMnO(3) thin film by resonant soft x-ray and hard x-ray diffraction. We observed a temperature-dependent incommensurate magnetic reflection below 45 K and a commensurate lattice-distortion reflection below 35 K. These results demonstrate that the ground state is composed of coexisting E-type and cycloidal states. Their different ordering temperatures clarify the origin of the large polarization to be caused by the E-type antiferromagnetic states in the orthorhombic YMnO(3) thin film.

We report on the results of x-ray absorption (XAS), x-ray magnetic circular dichroism (XMCD), and photoemission experiments on n-type Zn1−xCoxO (x = 0.05) thin film, which shows ferromagnetism at room temperature. The XMCD spectra show a multiplet structure, characteristic of the Co 2+ 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.

We have studied the electronic structure of the diluted magnetic semiconductor Ga 1−x Mn x N ͑x = 0.0, 0.02, and 0.042͒ grown on Sn-doped n-type GaN using photoemission and soft x-ray absorption spectroscopy. Mn L-edge x-ray absorption have indicated that the Mn ions are in the tetrahedral crystal field and that their valence is divalent. Upon Mn doping into GaN, new states were found to form within the band gap of GaN, and the Fermi level was shifted downward. Satellite structures in the Mn 2p core level and the Mn 3d partial density of states were analyzed using configuration-interaction calculation on a MnN 4 cluster model. The deduced electronic structure parameters reveal that the p-d exchange coupling in Ga 1−x Mn x N is stronger than that in Ga 1−x Mn x As.