Mössbauer study of ${\mathrm{CuCr}}_{0.1}$${\mathrm{Fe}}_{1.9}$${\mathrm{O}}_4$

${\mathrm{CuCr}}_{0.1}$ ${\mathrm{Fe}}_{1.9}$ ${\mathrm{O}}_4$ has been studied by Mössbauer spectroscopy and x-ray diffraction. The crystal structure is found to be a tetragonal spinel with the lattice parameters $a_0$=5.843 Å and $c_0$=8.578 Å. The Mössbauer spectra consist of two six-line patterns corresponding to ${\mathrm{Fe}}^{3+}$ at the tetrahedral (A) and octahedral (B) sites. Debye temperatures for A and B sites are found to be 677±5 and 288±5 K, respectively. The intensity ratio of the A to B patterns is found to increase at low temperatures with increasing temperature due to the large difference of Debye temperatures of the two sites and to decrease at high temperatures due to migration of ${\mathrm{Fe}}^{3+}$ ions from A sites to B sites.