Optical and magnetic properties of (1-x)BiFeO3-xCaTiO3 nanoparticles

Highlights: • Synthesis of (1-x)BiFeO3-xCaTiO3 nanoparticles (0.1 ≤ x ≤ 0.6). • Structural transformation from rhombohedral (R3c) to orthorhombic (Pbnm). • Small optical bandgap suggests usefulness for optoelectronic devices. • Improved magnetic properties due to released the latent magnetization. • May be useful for spintronics, optoelectronics, data storage. We report the structural, Raman, optical and magnetic properties of (1−x)BiFeO₃ -xCaTiO₃ (BF-xCT) nanoparticles. BF-xCT nanoparticles were synthesized through the sol-gel route in the large compositional range of 0.1 ≤ x ≤ 0.6. X-ray diffraction investigation shows the rhombohedral (R3c) phase structure for 0.1 ≤ x ≤ 0.2 and the orthorhombic (Pbnm) phase structure for 0.3 ≤ x ≤ 0.6. The transmission electron microscope (TEM) investigation confirms the well crystalline structure with the average particle size of 42 and 40 nm for x = 0.2 and 0.4, respectively. The changes in phonons frequencies and linewidths in Raman spectra reveals CT induced rhombohedral (R3c) to the orthorhombic (Pbnm) phase transition for x ≥ 0.3. The optical results shows strong absorption of visible light with small optical band gap values from 1.96 eV to 2.55 eV for BF-xCT with 0.1 ≤ x ≤ 0.6, indicating the possibility of its application in ultrafast optoelectronic devices. For all BF-xCT nanoparticles, magnetization studies at room-temperature exhibit hysteretic behavior with remnant magnetization, M_r ≤ 0.112 emu/g, which indicates that the CT substitution in the BF matrix released the latent magnetization.