  Among multifunctional double perovskite oxides, La2NiMnO6 has recently drawn
significant attention due to its importance both in terms of understanding of
fundamental physics and potential for device applications. The relative
alteration in Ni:Mn ratio strongly influences the structural, magnetic and
electrical properties of La2NiMnO6. In the present study, La2Ni1.5Mn0.5O6
sample with Ni:Mn = 3:1 ratio has been prepared using sol-gel method and
modifications of the above physical properties from that of a stiochiometric
sample of La2NiMnO6 are discussed. Rietveld analysis of X-ray diffraction data
shows that La2Ni1.5Mn0.5O6 samples belong to a major monoclinic structural
phase (P21/n), with partially disordered arrangement of Ni and Mn ions.
Magnetic characterization and X-ray absorption near edge structure analysis
reveal ferromagnetic ordering around 260 K between Ni2+ and Mn4+ ions while
spin glass like behavior is revealed at ~45 K. Semiconducting nature of the
sample was confirmed from temperature dependent resistivity measurements as
well as from the I-V characteristics measured at room temperature.
