Mössbauer studies of Cu1−xNixFeMnO4 spinel ferrites

Temperature dependence of the hyperfine fields in NiFe2O4 and CuFe2O4 oxides

“…Th e Mossbauer studies of the CuFez04 oxide has be en presented in refer enc e [1]. We made the NiFe z0 4 compound by solidstate reaction discussed in previous works [7][8][9]. Single phase formation of the compound was confirmed by X-r ay diffr action as shown in Fig.…”

“…3 we show th e variation of Mos sbauer spectrum shift from zero velocity with increasing sample measuring temperature. The shift in the Mossbauer spectrum con sists of isomer shift and second-or der Doppler shift resulting from the relative motion of the emitting 5 7 COnucl ei [9]. Th e isomer shift is not expe cte d to depend on temperature [11].…”

“…Th e hyp erfine fields Bhr(T) may be assumed to be directly proportional to the local magnetization C MC n) of the sample i.e. BhrCn ex M CT) [9]. Although this approximation has been used extensively in the literature to connect Mossbauer and magnetization data, it does not account for non-local contributions of to hyperfinẽ The temperature dependence of hyperfine fields can also be investigated on the basis of the Stoner theory.…”

“…From th e data of CuFe204 ar e more likely to be affected by the accuracy of measurement of temperature T of th e sample, determination of hyperfine fields [9], proximit y of T to Tc and the quality of the samples investigated. The log-log plots presented here appear to have th e advantage of indicating the temperature range where the exponents /31and /32 can reliably be deduced.…”

Temperature dependence of the hyperfine fields in NiFe2O4 and CuFe2O4 oxides

“…The measurements of hyperfine fields in ferrite materials have been routinely obtained in previous works [1][2][3][4][5][6][7][8][9][10]. However the temperature analysis of the hyperfine fields as a function of temperature (B hf (T)) has not been exhaustive [1][2][3][4][5][6][7][8].…”