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Thin films of cobalt have been prepared by nebulized spray pyrolysis using Co(acac)2 precursor in hydrogen atmosphere. The films show excellent magnetic and metallic properties. Granular Cu–Co alloy films of the composition Cu82Co18 and Cu50Co50 have been obtained by the nebulized spray pyrolysis of mixtures of Co(acac)2 and Cu(acac)2 in hydrogen atmosphere. These films show good magnetoresistance at room temperature.

Among the 2D materials, van der Waals heterostructures formed by vertically placing a monolayer of one 2D material over a single layer of another 2D material are gaining importance. As an alternative to such structures, ladder-like networks composed of two different 2D materials with an alternate arrangement of heterolayers can be generated by an electrostatic restacking strategy. The electrostatic restacking of 2D materials is achieved a great success. Various 2D/2D hetero-superlattices reported in the literature are MoS2/graphene, MnO2/Ti3C2, Ti3C2/graphene, NiAl–layered double hydroxides (LDHs)/graphene, and NiAl–LDHs/Ti3C2. The electrostatic restacking of different 2D materials generates novel 2D/2D hetero-superlattices. These hetero-superlattices display interesting electrocatalytic properties as supercapacitor electrodes, for water splitting reactions, as well as a noteworthy activity as cathode materials in lithium/sodium ion batteries. Ladder-like 3D networks of heterolayers obtained by phase-to-phase restacking improve charge-transfer interactions and the accessible area between active sites and electrolyte, thereby showing a higher electrocatalytic activity. The volumetric energy density of 32.6 Wh L−1 obtained with Ti3C2/graphene as a supercapacitor electrode is the highest reported among carbon-based materials. While the BCN/MoS2 superlattice shows a hydrogen evolution reaction (HER) activity comparable to Pt/C, unilamellar metallic MoS2/graphene and MnO2/graphene hetero-superlattices are reported to be efficient for both HER and sodium storage. The ambient instability of various 2D materials under electrocatalytic environments can be improved either by surface-functionalization or by forming hetero-superlattices.

Electrical and magnetic properties of four series of manganates Ln x Ca 1-x MnO 3 (Ln=La, Nd, Gd and Y) have been studied in the electron doped regime (x=0.02-0.25) in order to investigate the various inter-dependent phenomena such as ferromagnetism, phase separation and charge ordering.The general behavior of all the four series of manganates is similar, with some of the properties showing dependence on the average radius of the A-site cations, <r A > and cation size disorder.Thus, all the compositions show increase in magnetization at 100-120 K (T M ) for x<x max , the magnetization increasing with increasing x.The value of x max increases with decreasing <r A >, probably due to the increased phase separation induced by site disorder.This is also reflected in the larger width of the hysteresis loops at T<T M for small x or <r A >.In this regime, the electrical resistivity decreases with increasing x, but remains low and nearly constant T>T M .The percolative nature of the conduction mechanism at T<T M is substantiated by the fit of the conductivity data to the scaling law, σ ∝ |x c -x| p where p is in the 2-4 range.When x>x max , the materials become antiferromagnetic and charge-ordered at a temperature T CA , accompanied by a marked increase in resistivity.The value of T CA increases with increase in <r A > and x (upto x=0.3).Thus, all the four series of manganates are characterized by a phase-separated regime between x=0.02 and 0.1-0.15 and an antiferromagnetic charge-ordered regime at x>0.1-0.15.

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Isobaric gravimetric studies of PrOx and TbOx systems have shown the equilibrium existence of several non-stoicheiometric phases; the transformation temperatures found by differential thermal analysis agree well with the data from gravimetric studies. Oxidation reactions of Pr2O3 and Tb2O3 to non-stoicheiometric oxides generally show anomalously high entropy changes (ca.–25 e.u./mole of O2) compared with the value of ca.–44 e.u./mole of O2 generally found in oxidation of metals. The anomalous entropy changes are shown to arise from configurational factors. Cubic Pr2O3 with the defect structure is more readily oxidized than the hexagonal Pr2O3. Kinetic studies show that oxidation of Pr2O3 is a phase-boundary-controlled reaction.

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Review: MoS 2 , WS 2 , BN or BCN; 50 refs.

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Nanotubes constitute an exciting class of one‐dimensional nanomaterials of which carbon nanotubes are recognized widely as materials of importance. The possibility of having inorganic nanotubes was recognized early in the 1990s, accompanied by the report of nanotubes of MoS 2 and WS 2 . Since then, nanotubes of several inorganic materials have been prepared and characterized. While nanotubes of metal chalcogenides and oxides form a high proportion of the inorganic nanotubes investigated hither to, nanotubes of many other materials have also been prepared and characterized. Several synthetic strategies including both physical and chemical methods have been employed, of which the use of templates, precursors, and hydro‐ or solvothermal methods are prominent. In this article, we shall present a brief account of the present status of the synthesis of nanotubes of elemental materials as well as binary and complex metal oxides, chalcogenides, pnictides and carbides.

Compounds of the Y3-x Ba3+x Cu6O14+δ system, which YBa2Cu3O7-δ (x = 1) is member, have been prepared. A relatively low temperature nitrate decomposition method gives almost single phase compounds with tetragonal structure. The phases are metastable and show superconducting transitions (zero-resistance) around 50K.