Structural and magnetic characterization of $Bi_{0.9}Ca_{0.1}Fe_{0.98}X_{0.02}O_3$ (X = Mg, Al, Ti, V) polycrystalline multiferroic compounds

Abstract

The multiferroic compounds $Bi_{0.9}Ca_{0.1}Fe_{0.98}X_{0.02}O_3$ , X = {Mg, Al, Ti, V}, were prepared by the solid state reaction method and were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and differential scanning calorimetry. The compounds were found to have the rhombohedral perovskite-like structure, accompanied by the existence of small amounts of the usual impurity phases $Bi_2Fe_4O_9$ and $Bi_{25}FeO_{40.}$ The appearance of weak ferromagnetism is due to partial destruction of the spiral spin structure due to lattice distortion and suppression of oxygen vacancies. The magnetic transition temperatures of the compounds are 342, 346, 349, and 345 ◦ C, respectively.