Microstructural analysis, optical and magnetic properties of nanocrystalline Ni doped Dy2O3

Abstract Nanocrystalline samples of undoped dysprosium oxide (Dy 2 O 3 ) and Ni 2+ doped Dy 2 O 3 (Dy 1.90 Ni 0.10 O 3-δ /DNO) are prepared by co-precipitation method. X-ray diffraction (XRD) analysis by Maud software confirmed the desired crystallographic phase of both samples and also the substitution of Ni 2+ ion in Dy 2 O 3 lattice. Absence of impurity is confirmed from Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and high resolution transmission electron microscope (HRTEM) analysis. Magnetization vs. field (M-H) loop of DNO recorded at 5 and 10 K shows clear hysteresis loop with magnetization ∼138.71 emu/g at 5 K and ∼121.52 emu/g at 10 K with applied magnetic field of 5 T. The deviation of inverse susceptibility vs. temperature curve from Curie-Weiss fitting below ∼30 K and also the deviation of initial magnetization data of M-H loop recorded at 30 K from linear fitting suggests that the DNO is in mixed paramagnetic and ferromagnetic phase at and below ∼30 K. Defect mediated ferromagnetic ordering found in DNO at low temperature, is analyzed by bound magnetic polaron model.