Thermal hysteresis and domain states in Ni-Zn ferrites synthesized by oxalate precursor method

Nickel zinc ferrites with generic formula, Ni(X)Zn(1-X)Fe(2)O(4) (with X = 0.28-0.40) were synthesized by an oxalate precursor route starting with acetates to study their magnetic properties. The saturation magnetization versus temperature curves resemble those of R type ferrites. The system shows the presence of Yafet-Kittel type of spin. It is observed that magnetic moment (n(B)) values increase with the addition of Ni(2+). The remanance ratio R tends to increase with the addition of Ni(2+), which has been attributed to the increase of magnetocrystalline an isotropy constant (K1). The values of R compare well with the theoretical value (0.87). The coercive force (H(c)) tends to increase with the addition of Ni(2+), which has been related to the reverse domain formation. Studies on temperature variation of R and H(c) reveal that these parameters are thermally insensitive, which confirms the presence of multidomain grains in the material. These observations have been supported by a. c. susceptibility studies. (C) 2010 Elsevier B.V. All rights reserved.