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Title: Spin reorientation in multiferroic spinel Co{sub 0.5}Fe{sub 0.5}Cr{sub 2}O{sub 4} with Mössbauer spectroscopy

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.4918968· OSTI ID:22409984

We studied the magnetic properties of multiferroic spinel Co{sub 0.5}Fe{sub 0.5}Cr{sub 2}O{sub 4}, especially focusing on the spin-ordering, spin-reorientation, and charge re-distribution effects. From the Rietveld refinement analysis, the crystal structure was identified to be a normal cubic spinel of Fd-3m. Based on the temperature-dependent measurements of the magnetization and magnetic hyperfine field (H{sub hf}), Curie temperature (T{sub C}) of Co{sub 0.5}Fe{sub 0.5}Cr{sub 2}O{sub 4} was determined to be around 86 K where H{sub hf}  ≅  0. From the change of slope in the M-T curve, the conical-spiral magnetic ordering temperature was determined to be 20 K, which coincides with H{sub hf} measurement. Also, we have observed the decrease in the slope of the electric quadrupole splitting (ΔE{sub Q}) curve above 20 K, suggesting that the change in ΔE{sub Q} around T{sub S} is originated from charge redistribution due to the spin-relocation associated with the distortion of each tetrahedral site around Fe{sup 2+} ion above T{sub S}. This indicates that Co{sub 0.5}Fe{sub 0.5}Cr{sub 2}O{sub 4} has the noncollinear conical-spiral spin ordering with incommensurate spin structure below T{sub S}, while above T{sub S}, it has ferrimagnetic spin ordering with commensuration in the collinear state. In addition, the Jahn-teller distortion temperature is measured to be around 155 K, since both ΔE{sub Q} and Δ{sub 1} of {sup 5}T{sub 2g} band decrease rapidly with increasing temperature and disappear around 155 K.

OSTI ID:
22409984
Journal Information:
Journal of Applied Physics, Vol. 117, Issue 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
Country of Publication:
United States
Language:
English