A common behaviour of thermoelectric layered cobaltites: incommensurate spin density wave states in [Ca(2)Co(4)/(3)Cu(2/3)O(4)](0.62)[CoO(2)] and [Ca(2)CoO(3)](0.62)[CoO(2)]

作者：Sugiyama J^*; Brewer JH; Ansaldo EJ; Itahara H; Dohmae K; Xia C; Seno Y; Hitti B; Tani T

来源：Journal of Physics: Condensed Matter , 2003, 15(49): 8619-8630.

DOI：10.1088/0953-8984/15/49/031

Magnetism of a misfit layered cobaltite [Ca(2)Co(4/3)Cu(2/3)O(4)](x)(RS)[CoO(2)] (x similar to 0.62, RS denotes a rocksalt-type block) was investigated by a positive muon spin rotation and relaxation (mu(+)SR) experiment. A transition to an incommensurate (IQ spin density wave (SDW) state was found below 180 K (=T(C)(on)); and a clear oscillation due to a static internal magnetic field was observed below 140 K (=T(C)). Furthermore, an anisotropic behaviour of the zero-field mu(+)SR experiment indicated that the IC-SDW lies in the a-b plane, with oscillating moments directed along the c axis. These results were quite similar to those for the related compound [Ca(2)CoO(3)](0.62)(RS)[CoO(2)], i.e., Ca(3)Co(4)O(9). Since the]RS IC-SDW field in [Ca(2)Co(4/3)Cu(2/3)O(4)](0.62)(RS)[CoO(2)] was approximately the same]RS as those in pure and doped [Ca(2)CoO(3)](0.62)(RS)[CoO(2)], it was concluded that the IC-SDW exists in the [CoO(2)] planes.

• 出版日期2003-12-17