Spin glass ordering of Zn0.75Co0.25Fe0.5Cr1.5O4 cubic spinel

The linear and nonlinear low field AC susceptibilities of Zn0.75Co0.25Fe0.5Cr1.5O4 show peaks due to non-critical contributions, which mask the peak due to spin glass ordering. They extend into the region of temperatures in which Mössbauer spectra do not show any magnetic component. When a DC field of 200 Oe suppresses the non-critical contributions, peak due to spin glass ordering is clearly visible. The spin glass ordering is thus shown to be a thermodynamic transition. The critical exponent is found to fall within the range found using other spin glasses. Mössbauer spectra in zero fields provide TSG, which agrees with the peak temperature of AC susceptibilities in the absence of non-critical contributions. 〈SZ〉 determined using Mössbauer spectra does not show any anomaly. In the presence of a field of 5 T, the spectra show SG ordering at 4.2 K, which converts into ferrimagnetic ordering at higher temperatures.