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Ising-like Spin Anisotropy and Competing Antiferromagnetic - Ferromagnetic Orders in GdBaCo_{2}O_{5.5} Single Crystals

A. A. Taskin·A. N. Lavrov·Yoichi Ando
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Abstract

In RBaCo_{2}O_{5+x} compounds (R is rare earth), a ferromagnetic-antiferromagnetic competition is accompanied by a giant magnetoresistance. We study the magnetization of detwinned GdBaCo_{2}O_{5.5} single crystals, and find a remarkable uniaxial anisotropy of Co^{3+} spins which is tightly linked with the chain oxygen ordering in GdO_{0.5} planes. Reflecting the underlying oxygen order, CoO_2 planes also develop a spin-state order consisting of Co^{3+} ions in alternating rows of S=1 and S=0 states. The magnetic structure appears to be composed of weakly coupled ferromagnetic ladders with Ising-like moments, which gives a simple picture for magnetotransport phenomena.

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A. A. Taskin, A. N. Lavrov, Yoichi Ando. 2003-04-25. Ising-like Spin Anisotropy and Competing Antiferromagnetic - Ferromagnetic Orders in GdBaCo_{2}O_{5.5} Single Crystals. https://doi.org/10.1103/physrevlett.90.227201

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