Abstract
A series of polycrystalline multiferroic system
Mg
0.95
Mn
0.05
Fe
2
−
2
x
Ti
2
x
O
4
is prepared by a solid-state reaction route. The effect of
Ti
+
4
substitution in
Mg
0.95
Mn
0.05
Fe
2
−
2
x
Ti
2
x
O
4
has been studied using x-ray diffraction (XRD), Mössbauer spectroscopy, isothermal magnetization hysteresis, temperature dependent dc susceptibility, and temperature dependent dielectric measurements. Structural transformation from cubic spinel to tetragonal has been revealed from the XRD analysis. From the analysis of Mössbauer spectra, the decrease in hyperfine field at both tetrahedral and octahedral sites has been observed as a function of the concentration of
Ti
+
4
ions, which has been explained on the basis of a supertransferred hyperfine field. The appearance of the paramagnetic doublet within the sextet is due to the interaction of the electric field gradient (EFG) with the quadrupole moment of
Fe
57
nucleus and the decrease in magnetic interaction between Fe ions with Ti dilution. The variation in the quadrupole splitting indicates that the EFG changes with the increase in the substitution of
Ti
+
4
ions. Isothermal hysteresis loop shows the ferromagnetic behavior of
Mg
0.95
Mn
0.05
Fe
2
−
2
x
Ti
2
x
O
4
and the saturation magnetization is decreased with the increase in the substitution of
Ti
+
4
, which is explained by the weakening of the exchange interaction in the system. The dielectric measurements of these samples exhibit ferroelectric transition depending upon the concentration of the
Ti
+
4
.