La 2 NiMnO 6 (LNMO) was prepared by a combustion method followed by heating at high temperature. Subsequently, the preformed LNMO was annealed in air, oxygen, or N 2 atmosphere and characterized by powder x-ray diffraction (XRD), neutron diffraction, superconducting quantum interference device magnetometry, and dielectric analysis. Structural studies by XRD and neutron diffraction revealed the coexistence of partially cation disordered monoclinic (31%) and rhombohedral (69%) phases in the sample annealed in air. However, the sample annealed in oxygen shows about 50:50% of monoclinic and rhombohedral phases. Relaxor-like behavior with relative permittivity of the order of 10 4 was observed in the sample annealed in air, while relative permittivity decreases to about 200 in samples annealed in oxygen atmosphere. The magnetic properties indicate a well-defined ferromagnetic phase in the oxygen-annealed sample compared to a feeble ferromagnetic signature in the air-annealed one. The dielectric and ferromagnetism of LNMO samples have been related to formation and annihilation of oxygen vacancies.

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We report the surface morphology dependent enhanced field electron emission properties of copper oxide thin films, which are sputter deposited at two different incidence angles. The turn-on field is as low as 1.3 V µm -1 for obliquely deposited thin film, with an enhancement factor of ~ 5144. The emission current also shows good stability. With the help of finite element method analysis, we show that the enhanced field emission behaviour is due to the special surface topography of obliquely deposited film. While for the normally deposited film screening effect plays important role and thereby condemning the electron emission performance. We expect to have a general applicability of this study in the design of thin film based electron emitters.Recently Das et al., reported lowest turn-on field value of 0.9 V µm -1 for cupric oxide (CuO) nanoknife arrays. 22 On the other hand Deo et al., reported field emission property of Cu 2 O/ZnO hetero-nanobrush and found the turn-on field to be 6.5 V µm -1 (at a current density of 10µA cm -2 ). 23 Shi et al., reported that Surface morphology dependent field electron emission characteristic of copper oxide thin films shows superior field emission of obliquely sputter deposited thin film (turnon field ~ 1.3 V µm -1 ) than normally deposited film.

A facile one-pot hydrothermal synthesis of hollow ball-like ZnS nanostructures is reported using cysteamine, an ecofriendly sulfur source. Following similar protocol, a heterostructure of RGO-ZnS nanocomposite have been synthesized. The as-synthesized samples are structurally and optically characterized using different techniques. The photocatalytic activity of RGO-ZnS has been found to be ∼9% higher than that of ball-like ZnS nanostructures at a dose of 0.4 g/L. This result is attributed to the improved charge transport by hindering charge recombination of photoinduced excitons. One of the significant findings of this work is that the model anionic dye degraded better under alkaline condition with ZnS whereas the trend is reversed for RGO-ZnS composite. The removal efficiency of both the systems is allied with structural, morphological, and optical properties to understand the underlying mechanism of synthesis as well as photocatalysis process.

Low energy nitrogen ions are used in this work to manipulate wetting properties of the surface of the array of Cu2O nano-columns, which yields remarkable results. The nano-columnar thin films were grown on a highly conductive silicon surface by a sputter deposition technique. The films were irradiated at two different fluences of 5 × 10(15) and 1 × 10(16) ions per cm(2), respectively. With increasing fluence the shape of column tip changes, columns are bent and porous channels between columns are clogged up. While the surface of the pristine sample is hydrophilic, the irradiated surface turns into hydrophobic but having adhesion properties. We have analysed the structural and chemical properties of the surface in detail to understand the initial and modified wetting properties. Furthermore, the temporal evolutions of different droplet parameters are investigated to realize the interactions between the water droplet, the sample surface and the atmosphere. We envisage that such modified surfaces can be beneficial for transport of a small volume of liquids with minimum loss and spectroscopic studies, where a small amount of water droplet is available for measurements.

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