Microscopic evidence of spin state order and spin state phase separation in layered cobaltites RBaCo2O5.5 with R=Y, Tb, Dy, and Ho

H Luetkens; M Stingaciu; Yu G Pashkevich; K Conder; E Pomjakushina; A A Gusev; K V Lamonova; P Lemmens; H-H Klauss

doi:10.1103/PhysRevLett.101.017601

Microscopic evidence of spin state order and spin state phase separation in layered cobaltites RBaCo2O5.5 with R=Y, Tb, Dy, and Ho

Phys Rev Lett. 2008 Jul 4;101(1):017601. doi: 10.1103/PhysRevLett.101.017601. Epub 2008 Jul 2.

Authors

H Luetkens¹, M Stingaciu, Yu G Pashkevich, K Conder, E Pomjakushina, A A Gusev, K V Lamonova, P Lemmens, H-H Klauss

Affiliation

¹ Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland. hubertus.luetkens@psi.ch

PMID: 18764150
DOI: 10.1103/PhysRevLett.101.017601

Abstract

We report muon-spin relaxation measurements on the magnetic structures of RBaCo2O(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 Co3+ of CoO6 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.