Spin state and phase competition in TbBaCo_{2}O_{5.5} and the lanthanide series LnBaCo_{2}O_{5+δ} (0<=δ<=1)

Abstract

A clear physics picture of TbBaCo${}_2$O${}_{5.5}$ is revealed on the basis of density functional theory calculations. An antiferromagnetic (AFM) superexchange coupling between the almost high-spin Co${}^{3+}$ ions competes with a ferromagnetic (FM) interaction mediated by both p-d exchange and double exchange, being responsible for the observed AFM-FM transition. And the metal-insulator transition is accompanied by an xy/xz orbital-ordering transition. Moreover, this picture can be generalized to the whole lanthanide series, and it is predicted that a few room-temperature magnetoresistance materials could be found in LnBa${}_{1-x}$A${}_x$Co${}_2$O${}_{5+\delta }$ (Ln=Ho,Er,Tm,Yb,Lu; A=Sr,Ca,Mg).

13 pages, 2 figures; to be published in Phys. Rev. B on 1st Sept. Title and Bylines are added to the revised version

Cited by in corpus (13)

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• Spin structure and magnetic phase transitions in TbBaCo2O5.5
• Microscopic Evidence of Spin State Order and Spin State Phase Separation in Layered Cobaltites RBaCo2O5.5 with R=Y, Tb, Dy, and Ho
• X-ray Diffraction Study of Superstructure in GdBaCo2O5.5
• First principles study of the spin state transitions in GdBaCo${}_2$O${}_{5.5}$
• Effect of Oxygen Content on Magnetic Properties of Layered Cobaltites PrBaCo2O5+δ
• Probing phase coexistence and stabilization of the spin-ordered ferrimagnetic state by Calcium addition in the YBa_{1-x}Ca_{x}Co_{2}O_{5.5} layered cobaltites using neutron diffraction
• Magnetic and Electronic properties of Eu0.9Ca0.1BaCo2O5.5+? with the disparity of Oxygen Stoichiometry
• Infra-red Spectroscopic Studies of GdBaCo2O5.5
• Electron doping induced magnetic glassy state in phase separated YBaCo${}_2$O${}_{5.5-\delta }$
• Coupling of magnetism and transport properties to the lattice degrees of freedom in NdBaCo${}_2$O${}_{5+\delta }$ ($\delta \sim 0.65$)