Effect of Quantum Confinement on Optical and Magnetic Properties of Pr-Cr-Codoped Bismuth Ferrite Nanowires

We report the effect of the variation of diameter on the optical, magnetic, and magnetodielectric properties of the Pr-Cr-codoped BiFeO3 (BFO) nanowires (NWs). Pr-Cr-codoped BFO NWs with different diameters (18, 35, 55, 100, 150, and 250 nm) have been fabricated by employing a simple wet chemical template assisted route. The effect of quantum confinement has been found to have a significant influence on the room temperature photoluminescence and Raman spectra of the NWs. An interesting blue shift in the band gap emission is observed in the photoluminescence spectra of the NWs as a result of quantum confinement The position and the intensity of the Raman peaks are found to change significantly depending on the variation in the NW diameter. The room-temperature ferromagnetism of the codoped BFO NWs increases consistently with the decrease in the diameter of the NWs because of the suppression of the spiral spin structure and the increase in the number of uncompensated for spins at the NW surface (as the surface to volume ratio increases with the decrease in the NW diameter). Strong magnetoelectric coupling is evidenced in the codoped BFO NWs with the decrease in the NW diameter. The tuning of the optical, magnetic, and magnetodielectric properties of the doped BFO NWs appears to be very promising for achieving multifunctionality in a single material.