THE CHARACTERIZATION AND MAGNETIC PROPERTIES OF NANO-SIZED BISMUTH FERRITES SYNTHESIZED BY A NEW REVERSE MICELLE METHOD

Multiferroic materials possess electric and magnetic orderings simultaneously, making it possible to manipulate the electric state of a multiferroic by magnetic field, or vice versa. Among all single-phase multiferroics, BiFeO3 is particularly exciting, because it is regarded as one of the few materials with coexisting ferroelectricity and antiferromagnetism at room temperature. Improvement in magnetic properties at room temperature has been observed in single crystalline bismuth ferrite nanoparticles which show strong size-dependent magnetic properties. The nanoparticles of BiFeO3 were prepared by a new reverse micelle process. BiFeO3 phase with R3c symmetry was obtained by controlling the chemical precipitation process, pH level and calcination temperature. The X-ray diffraction (XRD), FT-IR, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were employed to probe the structural and magnetic properties of samples. Results indicated that BiFeO3 powders are formed with R3c crystal structure. Through this method, that is, the use of a surfactant and a new solvent, which are low in cost, both fine particles (40 nm) and a uniform distribution can be obtained. The magnetic measurements revealed that the magnetic properties are improved, as compared to the bulk samples.

Keywords:

bismuth ferrite , multiferroic , nanoparticle , perovskite structure