Enhanced magnetic and ferroelectric properties of La 1 − x M x FeO 3 (M = Dy and Y) nanoparticles: A comparison of A-site doping

The room temperature magnetic hysteresis (M-H) loops reveal ferromagnetic-like behavior in an antiferromagnetically ordered LaFeO 3 (LFO) material system synthesized by the sol–gel method. The maximum magnetization (M m a x ) for the undoped sample annealed at 800 °C is 1.08 emu/g, whereas, with the same annealing, materials that are Dy and Y doped (25%) exhibit four times higher magnetization. It is interesting to note that non-magnetic ion Y 3 + doped LFO has the same magnetization as magnetic ion Dy 3 + doped nanomaterials. Reduction of particle and crystallite size plays a significant role in enhancing the net magnetization of doped materials. While the magnetization in Y-doped materials is attributed to the anti-symmetric exchange interaction (AEI) through spin canting, the greater magnetization for Dy doped samples is related to the AEI as well as inherent magnetic moment of the Dy 3 + ion. The quantified tilting angle (Fe–O–Fe) is higher and the bond length (Fe–O) is smaller for Y-doped compounds compared to Dy-doped samples. X-ray photoelectron spectroscopy for oxygen 1s spectra shows that the relative area of O 1 − is higher in Dy-doped LFO than Y-doped sample. Ferroelectric hysteresis loops exhibit spontaneous electric polarization with reduced leakage current for Y-doped LFO, while other compounds show leaky behavior.