Structural, electrical and magneto-electric characteristics of BiMgFeCeO6 ceramics

The polycrystalline sample of double perovskite BiMgFeCeO6 was prepared by a standard ceramics processing technique (high-temperature solid-state reaction). Preliminary structural analysis using X-ray diffraction data has exhibited the formation of the material in orthorhombic system. Detailed studies of electrical properties (permittivity (dielectric constant), tangent loss, electrical modulus, conductivity and impedance) of the material as a function of frequency (1 kHz-1 MHz) at different temperatures (25-500 °C) have provided many interesting results on conduction mechanism, structure-properties relationship, etc. An important role of interface in getting high dielectric material has been realized. The existence of space charge polarization and Maxwell-Wagner relaxation in the material, particularly at low frequencies and high temperatures, has been observed. Nyquist plots discuss the temperature-dependent contributions of grain, grain boundary and electrode effect. The nature and existence of the hysteresis loop confirmed the ferroelectric characteristics of the material at room temperature. Study of dc conductivity of the compound with temperature exhibits presence of negative temperature coefficient of resistance (NTCR) characteristics in it. An optical energy band gap of ∼2.9 eV was determined from the UV-visible absorbance spectrum. A unique data on magneto-electric (ME) coefficient, measured by varying dc bias magnetic field, was obtained.