Structural, magnetic and electronic properties of Fe0.5Cu0.5Cr2S4

Autor:	C. Greaves, H. M. Palmer
Rok vydání:	1999
Předmět:	Crystallography Nuclear magnetic resonance Magnetic moment Ferromagnetism Magnetic structure Chemistry Neutron diffraction Materials Chemistry General Chemistry Crystal structure Electronic structure Manganite Magnetic susceptibility
Zdroj:	Journal of Materials Chemistry. 9:637-640
ISSN:	1364-5501 0959-9428
DOI:	10.1039/a809032g
Popis:	The crystallographic and magnetic structures of Fe 0.5 Cu 0.5 Cr 2 S 4 have been examined in order to generate a possible mechanism to explain the CMR behaviour of such spinels. Neutron powder diffraction has revealed that the tetrahedrally coordinated Fe 3+ and Cu + ions are fully ordered, with the magnetic moments of Fe 3+ (µ 300 =–1.97(5) µ B ) aligned antiparallel to those of the octahedrally coordinated Cr 3+ (µ 300 =1.49(3) µ B ). The results suggest a new CMR mechanism, which involves exchange on three cation centres (‘triple exchange’) and requires antiferromagnetic coupling of magnetic spins, in contrast to the manganite perovskites for which double-exchange provides a ferromagnetic state.
Databáze:	OpenAIRE
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