Mössbauer study of ${\mathrm{CuFe}}_{0.7}$${\mathrm{Cr}}_{1.3}$${\mathrm{O}}_4$

Ferrimagnetic ${\mathrm{CuFe}}_{0.7}$ ${\mathrm{Cr}}_{1.3}$ ${\mathrm{O}}_4$ has been investigated over a temperature range from 4.2 to 347 K using the Mössbauer technique. X-ray diffraction shows that it has a cubic spinel structure and a lattice constant of $a_0$=8.346±0.005 Å. The isomer shift indicates that iron ions are ferric and located at the tetrahedral sites. Its Néel temperature $T_N$ is found to be 343±2 K. As the temperature increases toward $T_N$ a systematic line broadening effect in the Mössbauer spectrum is observed and interpreted to originate from different temperature dependencies of the magnetic hyperfine fields at various iron sites.