Structural phase transition in CuFe{sub 2}O{sub 4} spinel

Journal Article · Sun Sep 15 04:00:00 EDT 2013 · Crystallography Reports

DOI:https://doi.org/10.1134/S1063774513040044· OSTI ID:22210526

Bobrikov, I. A.; Maschenko, M. S.; Sangaa, D.; Simkin, V. G. ^[1]

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1. Joint Institute for Nuclear Research (Russian Federation)

A structural transition with a reduction in symmetry of the high temperature cubic phase (sp. gr. Fd3m) to the tetragonal phase (sp. gr. I4{sub 1}/amd) and the appearance of a ferrimagnetic structure occur in CuFe{sub 2}O{sub 4} copper ferrite at T Almost-Equal-To 440 Degree-Sign C. It is established by an experiment on a high-resolution neutron diffractometer that the temperature at which long-range magnetic order occurs is higher than that of tetragonal phase formation. When cooling CuFe{sub 2}O{sub 4} spinel from 500 Degree-Sign C, the equilibrium coexistence of both phases is observed in a fairly wide temperature range ({approx}40 Degree-Sign C). The composition studied is a completely inverse spinel in the cubic phase, and in the tetragonal phase the inversion parameter does not exceed few percent (x = 0.06 {+-} 0.04). At the same time, the phase formed upon cooling has a classical value of tetragonal distortion ({gamma} Almost-Equal-To 1.06). The character of temperature changes in the structural parameters during the transition from cubic to tetragonal phase indicates that this transition is based on the Jahn-Teller distortion of (Cu,Fe)O{sub 6} octahedra rather than the mutual migration of copper and iron atoms.

• OSTI ID: 22210526
• Journal Information: Crystallography Reports, Journal Name: Crystallography Reports Journal Issue: 5 Vol. 58; ISSN 1063-7745; ISSN CYSTE3
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER
CUBIC LATTICES
FERRITE
FERRITES
JAHN-TELLER EFFECT
NEUTRONS
SPINELS
TEMPERATURE RANGE 0400-1000 K
TETRAGONAL LATTICES