Artículos de revistas
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
Registro en:
Physical Review B. American Physical Soc, v. 70, n. 21, 2004.
1098-0121
WOS:000226111400078
10.1103/PhysRevB.70.214416
Autor
Granado, E
Huang, Q
Lynn, JW
Gopalakrishnan, J
Ramesha, K
Institución
Resumen
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 T(c)similar to200-250 K, with an average ordered moment of similar to1.8-2.0mu(B)/(Mn,Ru). The observation of long-range ferromagnetism and the absence of orbital ordering are rationalized in terms of a strong Mn-Ru hybridization, which may freeze the orbital degree of freedom and broaden the e(g) valence band, leading to an orbital glass state with carrier-mediated ferromagnetism. 70 21