Investigation of magnetic phase transitions in dilute copper ferrites

Mössbauer spectra of copper ferrites CuGa x Al 2 x Fe 2 − 3 x O 4 ( x = 0.3, 0.4, 0.5) have been measured at temperatures in the range from 90 to 295 K. The degree of disturbance of long-range magnetic order has been determined as a function of the temperature. The Curie temperature has been found for the composition with x = 0.5, and the dependence of the Curie temperature on the concentration of the nonmagnetic impurity has been constructed.