Abstract
A series of samples in the system Ni
0.65
Zn
0.35
Cu
x
Fe
2-x
O
4
(x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by the usual ceramic technique. The thermoelectric power and the magnetic susceptibility were measured. The transition from the ferrimagnetic to the paramagnetic state is accompanied by an increase in the thermo EMF. NiZn ferrite shows n-type conductivity due to the presence of Fe
2+
ions. The addition of Cu
2+
ions creates lattice vacancies which give rise to p-type conductivity.
The Tawfik coefficient was determined for NiZn ferrite in the paramagnetic state. This coefficient was reduced by addition of Cu up to x < 0.5.