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Abstract: The dielectric response of pulsed laser ablated Bi1.5Zn1.0Nb1.5O7 (BZN) thin films are investigated within the temperature range of 300–660 K and frequency range of 100 Hz–100 kHz. Thin film exhibited a strong dielectric relaxation behavior. A sharp rise in dielectric constant of BZN thin film at high temperatures is related to disorder in cation and anion lattices. Observed dielectric relaxation implies a redistribution of charges within the unit cell. This phenomenon suggests that the large change in dielectric constant is due to a dynamical rise of dipolar fluctuations in the unit cell. XPS spectra of BZN (A2B2O6O′) cubic pyrochlore, confirm that the relaxation corresponds to the ionic hopping among the A and O′ positions of several local potential minima. Barrier height for hopping is distributed between 0 and 0.94 eV. The O spectrum confirms presence of two types of oxygen in BZN thin film. The disorder in charge neutralized thin film is correlated with XPS spectra. [ABSTRACT FROM AUTHOR]

Thin films of Ba(Zr0.1Ti0.9)O3 were deposited by pulsed excimer laser ablation technique on Pt substrates. The films were polycrystalline in nature. The room temperature dielectric constant was 450 at a frequency of 100 kHz. Studies indicated that deposition temperature and pressure both have an effect on the crystallinity of the films deposited. The films showed a slightly diffused phase transition in the range of 230–300 K. The ferroelectric nature of the film was confirmed by the polarization hysteresis curves. The saturation and remanent polarization were 13.4 and 5.9 μC/cm2, respectively, with a coercive field of 45 kV/cm. The dispersion in both the real and the imaginary parts of the dielectric constant at low frequencies with increase in temperature was attributed to the space charge contribution to the complex dielectric constant. [Copyright &y& Elsevier]

Abstract: Epitaxial heterostructures of La0.6Sr0.4MnO3/0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 were fabricated on LaNiO3 coated LaAlO3 (100) substrates by pulsed laser ablation. Ferromagnetic and ferroelectric hysteresis established their biferroic nature. Dielectric behaviour studied under different magnetic fields over a wide range of temperatures revealed that the capacitance in these heterostructures varies with the applied magnetic field. Appearance of magnetocapacitance and its dependence on temperature and magnetic field strength strongly indicated the possibility of strain mediated magnetoelectric coupling in these heterostructures. [Copyright &y& Elsevier]

CuIn1−xAlxSe2 (CIASe) thin films with x=0.25, 0.5 and 0.65 were prepared by four-source elemental evaporation. The structural and optical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive analysis, and optical transmission. The results showed that these films contain chalcopyrite structure with preferred orientation along (112) direction. The morphology, grain distribution and composition of CIASe films were studied and compared for different Al content. The optical studies revealed that the films were highly absorbing and the energy band gap calculated from transmission spectra for x=0.25, 0.5 and 0.65 were 1.2, 1.51 and 1.73 eV, respectively. The variation of Al content in the CIASe composition offered a very effective change in the optical band gap. [Copyright &y& Elsevier]

Lanthanum modified lead titanate (PLT) thin films are one of the potential candidates for the pyroelectric and memory applications due to their excellent dielectric, pyroelectric and ferroelectric properties. PLT thin films with 25 at.% of La were deposited on platinum coated Si substrates by the laser ablation technique. The phase transition studies were done in the temperature range of −40 to 150 °C as a function of frequency and ac field. A diffused phase transition with the shifting of the maximum dielectric permittivity (∊max) to higher temperatures with the increase of frequency and dielectric dispersion with frequency at the lower temperatures were observed. The variation of the temperature corresponding to maximum dielectric constant Tm, with frequency follows the Vogel–Fulcher relation, which is the characteristic of the relaxor-like behavior of the material. With the increase of ac drive, the Tmax was shifted to lower value. [Copyright &y& Elsevier]

Abstract: Ferroelectric bismuth vanadate Bi2VO5.5 (BVO) thin films have been successfully grown on p-type Si(100) substrate by using chemical solution decomposition (CSD) technique followed by rapid thermal annealing (RTA). The crystalline nature of the films has been studied by X-ray diffraction (XRD). Atomic force microscopy (AFM) was used to study the microstructure of the films. The dielectric properties of the films were studied. The capacitance–voltage characteristics have been studied in metal–ferroelectric–insulator–semiconductor (MFIS) configuration. The dielectric constant of BVO thin films formed on Si(100) is about 146 measured at a frequency of 100kHz at room temperature. The capacitance–voltage plot of a Bi2VO5.5 MFIS capacitor subjected to a dc polarizing voltages shows a memory window of 1.42V during a sweep of ±5V gate bias. The flatband voltage (V f) shifts towards the positive direction rather than negative direction. This leads to the asymmetric behavior of the C–V curve and decrease in memory window. The oxide trap density at a ramp rate of 0.2V/s was estimated to be as high as 1.45×1012 cm−2. [Copyright &y& Elsevier]

Polycrystalline thin films of Ba(Sn0.1Ti0.9)O3 were deposited on Pt coated silicon substrates by pulsed excimer laser ablation technique. The room temperature dielectric constant of the Ba(Sn0.1Ti0.9)O3 films was 350 at a frequency of 100 kHz. The films showed a slightly diffused phase transition in the range of 275–340 K. The polarization hysteresis behavior confirmed the ferroelectric nature of the thin films. Remanent polarization (Pr) and saturation polarization (Ps) were 1.1 and 3.2 μC/cm2, respectively. The asymmetric capacitance–voltage curve for Ba(Sn0.1Ti0.9)O3 was attributed to the difference in the nature of the electrodes. Dispersion in both the real (ϵ′r) and imaginary (ϵ″r) parts of the dielectric constant at low frequencies with increase in temperature was attributed to space charge contribution in the complex dielectric constant. [Copyright &y& Elsevier]