Growth and magnetic properties of new lead-free (1 − x)Bi1/2Na1/2TiO3 + xBi(Ti1/2Co1/2)O3 solid solution materials

The new solid solution system of (1 − x)Bi1/2Na1/2TiO3 + xBi(Ti1/2Co1/2)O3 materials was fabricated using the sol–gel method. The structural studies via X-ray diffraction and Raman scattering indicated that Bi(Ti1/2Co1/2)O3 materials were well dissolved into host Bi1/2Na1/2TiO3 materials to follow the rhombohedral structure of host materials. The diffuse cations of Bi(Ti1/2Co1/2)O3 to random incorporation with host lattice to form as solid solution in host Bi1/2Na1/2TiO3 materials resulted in distortion lattice parameter and reduced the optical band-gap values from 3.06 to 2.32 eV for pure and 9 mol% Bi(Ti1/2Co1/2)O3 solute into host Bi1/2Na1/2TiO3 materials. The compensative diamagnetism and weak ferromagnetism of pure Bi1/2Na1/2TiO3 materials were tuned to ferromagnetism at room temperature as increasing the Bi(Ti1/2Co1/2)O3 amounts solute into host Bi1/2Na1/2TiO3 materials. The observation of the room-temperature ferromagnetism in Bi(Ti1/2Co1/2)O3-modified Bi1/2Na1/2TiO3 system was important to integrate the ferromagnetic properties in lead-free ferroelectric materials for further application in smart electronic devices which were required multifunctional materials.