Some interesting observations on the magnetic and electric properties of Al3+ doped lanthanum orthoferrite (La0.5Al0.5FeO3)

Aluminum doped lanthanum orthoferrite (La0.5Al0.5FeO3) (LAFO) has been prepared by solid state reaction method. The crystallographic phase of the sample has been confirmed by X-ray diffraction. The static magnetic susceptibility (chi(m)) of the sample at different magnetic fields has been measured in the temperature range 300-14 K. The magnetization of the sample measured at room temperature increases non-linearly with the increase of magnetic field, which suggests the presence of dipole-dipole/exchange interaction in the sample. Magnetization and chi(m) have been considerably enhanced compared to LaFeO3. The dynamic hysteresis loops of the sample observed at room temperature also indicates the presence of hysteretic behavior of the sample. Though the LaFeO3 is an antiferromagnetic insulator, the resistivity measured in the temperature range 300-470 K showed that LAFO is a semiconducting material with low resistivity. The variation of dielectric constant as a function of frequency and temperature predicts the presence of spontaneous polarization in the sample. (C) 2010 Elsevier Ltd. All rights reserved.