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Structural, dielectric and ferroelectric measurements of polycrystalline BaTi 1 − x Sn x O 3 (x=15%) are reported. Detailed temperature dependent dielectric, x-ray diffraction and ferroelectric loop (P-E) measurements indicate the sequence of paraelectric and phase coexistence (ferroelectric and relaxor) phase as a function of lowering temperature. Hysteresis behavior observed in maximum polarization is envisaged as the signature of disorder induced first order phase transition in the phase co-existence region. The evidence for the possibility of tuning phase fraction in the phase co-existence region with electric field as a variable similar to that of magnetic materials with magnetic field is reported.

We report the structural and magnetic properties of as-deposited and thermally annealed FePt/C granular multilayer films. The as-deposited system exhibits a disordered fcc FePt phase with an average grain size of 3 nm. Thermal annealing at 650 °C results in partial L 1 0 ordering and an associated grain growth to 7 nm. Mossbauer measurements show that there is no non-magnetic component present, suggesting that carbon resides only in the grain boundary region. The ferromagnetic grains are magnetically decoupled.

Temperature and frequency dependence of the real (e′) and imaginary (e″) parts of the dielectric permitivity of cubic Ba(Ti0.7Hf0.3)O3 ceramic has been studied in the temperature range of 100 K to 350 K at the frequencies 0.1 kHz, 1 kHz, 10 kHz, 100 kHz for the first time. Diffuse phase transition and frequency dispersion is observed in the permittivity-vs-temperature plots. This has been attributed to the occurrence of relaxor ferroelectric behavior. The observed relaxor behavior has been quantitatively characterized based on phenomenological parameters. A comparison with the Zr doped BaTiO3 has also been presented. For Hf doped samples transmission electron microscopy (TEM) characterization do show the presence of highly disordered microstructure at length scales of few tens of nano-meters.

Temperature dependent electron diffraction of La 1− x Ca x MnO 3 for 0.55≤ x ≤0.67 using transmission electron microscope (TEM) has been carried out in the temperature range of 106–300 K to study the melting of charge-ordering across the transition temperature. Clear signature of charge-ordering as evident by the presence of diffuse super-lattice spots persist even at room temperature. This has been consistently observed for four different samples with compositions within the range of 0.55≤ x ≤0.67. The results indicate emergence of some degree of itinerancy in the localized charge carriers as temperature rises.

The problem of identification of the correct crystalline structure of CdS nanoclusters below 2.5 nm in size is outlined. Structure of thiophenol capped CdS nanoclusters in the size range 1.2–4.3 nm, synthesized using cadmium acetate solution in methanol, is discussed using powder XRD and electron diffraction data. Unambiguous confirmation of the wurtzite phase in CdS nanoclusters below 2.5 nm size is reported. The observation of 102 wurtzite peak in the XRD patterns of such nanoclusters indicates low stacking fault concentration.