Effect of Sm-Substitution on Structural, Electrical and Magnetic Properties of BiFeO3

Samarium-modified bismuth ferrites (i.e., Bi1-xSmxFeO3 (BSFO; x = 0, 0.05, 0.15, 0.25) were synthesized in a single-phase by a solid-state reaction method. Preliminary x-ray structural analysis suggested that crystal structure of the material is rhombohedral for x = 0.0, 0.05, 0.15 and orthorhombic for x = 0.25 composition. The surface morphology and textures of the pellet samples, recorded by scanning electron microscope at room temperature, show uniform distribution of the different size of plate- and rod-shaped grains on the surface of the samples. The grain size generally decreases with increase of Sm-content in BSFO. Detailed studies of permittivity and impedance parameters of the samples in a wide frequency range (1 kHz - 1 MHz) at different temperatures (30 degrees C - 450 degrees C) provide many new and interesting results about relaxation processes. Room temperature magnetic hysteresis loops revealed that the spontaneous magnetization increases due to structural distortion and partial destruction of spiral spin structure caused by the substitution of Sm in BiFeO3. Enhancement in magneto-electric coupling coefficient of BFO was observed with increase of Sm in BSFO.