Home| 題 目 | Unconventional magnetic order and dynamics in 1-2-10 compounds: a neutron scatter's view |
| 講 師 | Jean-Michel Mignot（Laboratoire L�on Brillouin (CEA-CNRS), Saclay, France） |
| 日 時 | 2015年10月22日（木） 16:30- |
| 場 所 | 先端物質科学研究科 402N |
| 要 旨 | The Ce "1-2-10" compounds, with formula CeT2Al10 (T: transition metal element Fe, Ru, Os), form a novel class of materials with challenging magnetic properties. Whereas a Kondo insulator (KI) behavior is clearly observed in the temperature dependence of their electrical resistivity below room temperature, as well as in their optical conductivity spectra, both CeRu2Al10 and CeOs2Al10 exhibit a quite unusual long-range antiferromagnetic state, whose high ordering temperature (T0 = 27.3 and 28.7 K, respectively, as compared to only 16.5 K in GdRu2Al10), weak ordered moment, and paradoxical anisotropy are difficult to reconcile with conventional views of KIs. A general survey will be given of results obtained by a variety of neutron scattering techniques, especially regarding the relationship between the aforementioned static AFM order and the magnetic excitation spectra obtained from inelastic, unpolarized as well as polarized, neutron experiments. In the absence of AFM order, the low-temperature spectra measured for CeFe2Al10 exhibit a “spin-exciton”-like component reminiscent of archetype KI compounds like SmB6 or YbB12. Further insight gained from studying the evolution of the magnetic response in Ru-Rh solid solutions, or upon the application of a magnetic field, will also be discussed. |
| 担 当 | 世良 正文（先端物質科学研究科）・内線7020 |
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