Direct Observation of AntiferroQuadrupolar Ordering Resonant Xray Scattering Study of D.pdfVIP

Direct Observation of Antiferro-Quadrupolar Ordering – Resonant X-ray Scattering Study of DyB C – 2 2 1,4 1 1,4 2,4 2,3 2,4 1,4 K.Hirota , N.Oumi , T.Matsumura , H.Nakao , Y.Wakabayashi , Y.Murakami , and Y.Endoh 1Department of Physics, Tohoku University, Sendai, 980-8578 Japan 2Photon Factory, Institute of Materials Structure Science, KEK, Tsukuba 305-0801, Japan 3Department of Physics, Keio University, Yokohama 223-8522, Japan 4 CREST, Japan Science and Technology Corp., Tsukuba 305-0047, Japan 9 9 (February 1, 2008) 9 Antiferroquadrupolar (AFQ) ordering has been conjectured in several rare-earth compounds to 1 explain their anomalous magnetic properties. No direct evidences for AFQ ordering, however, have p been reported. Using the resonant x-ray scattering technique near the Dy LIII absorption edge, we e have succeeded in observing the AFQ order parameter in DyB C and analyzing the energy and 2 2 S polarization dependence. Much weaker coupling between orbital degrees of freedom and lattice in 1 4f electron systems than in 3d compounds provides an ideal platform to study orbital interactions originated from electronic mechanisms