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Crystal structures and magnetic order of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba): Possible orbital glass ferromagnetic state

Eduardo Granado·Qingzhen Huang·Jeff W. Lynn·J. Gopalakrishnan·K. Ramesha
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Abstract

The crystallographic and magnetic properties of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba) were investigated by means of neutron powder diffraction. All studied samples show the orthorhombic perovskite crystal structure, space group Pnma, with regular (Mn,Ru)O{6} octahedra and no chemical ordering of the Mn3+ and Ru4+ ions. Ferromagnetic spin structures were observed below Tc ~ 200-250 K, with an average ordered moment of ~ 1.8-2.0 Bohr magnetons per (Mn,Ru). The observation of long-range ferromagnetism and the absence of orbital ordering are rationalized in terms a strong Mn-Ru hybridization, which may freeze the orbital degree of freedom and broaden the eg valence band, leading to an orbital-glass state with carrier-mediated ferromagnetism.

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Eduardo Granado, Qingzhen Huang, Jeff W. Lynn, J. Gopalakrishnan, K. Ramesha. 2004-12-22. Crystal structures and magnetic order of La{0.5+delta}A{0.5-delta}Mn{0.5+epsilon}Ru{0.5-epsilon}O{3} (A= Ca, Sr, Ba): Possible orbital glass ferromagnetic state. https://doi.org/10.1103/physrevb.70.214416

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