Simple top-down preparation of magnetic Bi_0.9Gd_0.1Fe_1−xTi_xO₃ nanoparticles by ultrasonication of multiferroic bulk material

We present a simple technique to synthesize ultrafine nanoparticles directly from bulk multiferroic perovskitepowder. The starting materials, which were ceramic pellets of the nominal compositions Bi0.9Gd0.1-Fe1−xTixO3 (x = 0.00–0.20), were prepared initially by a solid state reaction technique, then ground intomicrometer-sized powders and mixed with isopropanol or water in an ultrasonic bath. The particle sizewas studied as a function of sonication time with transmission electron microscopic imaging and electrondiffraction that confirmed the formation of a large fraction of single-crystalline nanoparticles with a meansize of 11–13 nm. A significant improvement in the magnetic behavior of Bi0.9Gd0.1Fe1−xTixO3 nanoparticlescompared to their bulk counterparts was observed at room temperature. This sonication technique may beconsidered as a simple and promising route to prepare ultrafine nanoparticles for functional applications.