Room temperature antiferromagnetic ordering in chemically prepared nanocrystalline Co-doped neodymium oxide (Nd1.90Co0.10O3-δ)

Abstract

Nanocrystalline sample of Co-doped neodymium oxide (Nd1.90Co0.10O3-δ, NCO) is prepared by co-precipitation method. Rietveld analysis of the X-ray diffractograms confirms the formation of desired phase and complete substitution of Co-ions in Nd2O3 lattice. Analyses of transmission electron microscopy and the Raman spectra of NCO recorded at room temperature also substantiate this fact. Magnetization (M) as a function of temperature (T) and magnetic field (H) data shows that antiferromagnetic (AFM) ordering is introduced in the sample at room temperature and below ∼ 100 K, a transition from AFM to ferromagnetic (FM) phase is observed. Susceptibility vs. temperature (χ-T) curve in the temperature range of 300–100 K is successfully fitted by Johnston formula which indicates the coexistence of AFM and paramagnetic (PM) phase and below 100 K, the M-T curve is well fitted by a combined equation generated from three dimensional (3D) spin wave model and Curie-Weiss law which confirms the presence of mixed state of FM and PM phases. Oxygen vacancy mediated ferromagnetism plays an important role behind the onset of FM phase.