Magnetic and dielectric properties of alkaline earth Ca2+ and Ba2+ ions co-doped BiFeO3 nanoparticles

Abstract Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles, Bi 0.8 Ca 0.2− x Ba x FeO 3 ( x =0–0.20), were prepared by a sol–gel method. The phase structure, grain size, dielectric and magnetic properties of the prepared samples were investigated. The results showed that the lattice structure of the nanoparticles transformed from rhombohedral ( x =0) to orthorhombic ( x =0.07–0.19) and then to tetragonal ( x =0.20) with x increased. The dielectric properties of the nanoparticles were affected by the properties of the substitutional ions as well as the crystalline structure of the samples. The magnetic properties of the nanoparticles were greatly improved and the T N of the nanoparticles was obviously increased. All the Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles presented the high ratio of M r / M from 0.527 to 0.571 and large coercivity from 4.335 to 5.163 KOe.