Hall effect and dielectric properties of Mn-doped barium titanate

BaMn_xTi_1-xO₃ (0≤x≤0.01) ceramics have been prepared using a sol-gel method. The Hall coefficient, leakage conductance and dielectric constant were measured. The Hall effect confirms that the charge carriers of the ceramics are electrons, and the electronic concentration n=1/|eR| decreases with increasing Mn concentration. We propose that Mn³⁺ and Mn⁴⁺ substitution of Ti can partially trap the conductance electrons. The dielectric constant ε₁ of the pellets exhibited a peak at T_c∼110°C upon heating and the height and position of this peak depends on the Mn concentration. The Mn²⁺ incorporated in the oxygen octahedron of the BaTiO₃ unit cell is in a more centered position than Ti⁴⁺ and may, therefore, modify considerably the ferroelectric property.