Microscopic evidence of spin state order and spin state phase separation in layered cobaltites RBaCo(2)O(5.5) with R = Y, Tb, Dy, and Ho

作者：Luetkens H^*; Stingaciu M; Pashkevich Yu G; Conder K; Pomjakushina E; Gusev A A; Lamonova K V; Lemmens P; Klauss H H

来源：Physical Review Letters, 2008, 101(1): 017601.

DOI：10.1103/PhysRevLett.101.017601

We report muon-spin relaxation measurements on the magnetic structures of RBaCo(2)O(5.5) with R = Y, Tb, Dy, and Ho. Three different phases, one ferrimagnetic and two antiferromagnetic, are identified below 300 K. They consist of different ordered spin state arrangements of high-, intermediate-, and low-spin Co(3+) of CoO(6) octahedra. Phase separation into well separated regions with different spin state order is observed in the antiferromagnetic phases. The unusual strongly anisotropic magnetoresistance and its onset at the FM-AFM phase boundary is explained.

• 出版日期2008-7-4