A unique magnetic behavior and dielectric properties of Bi0.9–xLa0.1CaxFeO3 nanoparticles at room temperature

Ca2+ and La3+ ions co-doped BiFeO3 nanoparticles, Bi0.9–xLa0.1CaxFeO3 (BLCFOx) (x=0, 0.10, 0.13, 0.17 and 0.20), were prepared by a sol–gel method. X-ray diffraction analysis showed that the average grain size of the prepared samples was in the range of 24–19 nm. The lattice structure of the nanoparticles transformed from orthorhombic to cubic with Ca2+ ions substitution increased. Dielectric properties were measured up to high frequency ∼80 MHz. It was found that the co-doping of suitable amount of La3+ and Ca2+ ions was helpful to improve the dielectric properties of the samples. Magnetic properties of the samples were improved and all the co-doped samples presented a wasp-waisted hysteresis loop, which was rarely reported in BFO. Characteristics of wasp-waisted hysteresis loops show low hysteresis loss in low magnetic fields, and are helpful to design some multiferroic devices.

► Samples were prepared using a sol–gel method.
► Co-doped samples with suitable amount presented good dielectric properties.
► All co-doped samples presented a wasp-waisted hysteresis loop.
► The wasp-waisted hysteresis loop was rarely reported in BFO.