Microstructure and critical current densities of laser ablated YBa2Cu3O7−δ thin films doped with 2–20 wt. % Ag have been studied. A critical current density as high as 1.4×107 A cm−2 at 77 K has been realized on 〈100〉 SrTiO3 substrates with YBaCuO films doped with 5 wt. % Ag which has been found to be the optimum. Evidence indicates that the improved microstructure and epitaxy which is a consequence of grain enlargement and alignment caused by Ag is responsible for the high values of critical currents observed.

The advantages offered by ferroelectric PbTiO 3 films deposited directly onto silicon in memory applications, field effect devices and pyroelectric detectors have stimulated intense research activity. This review covers work carried out during the last several years on their growth, characterization and device fabrication using ferroelectric thin films of PbTiO 3 on single-crystalline Si substrate with and without buffer layers.

Room temperature coexistence of ferromagnetism and ferroelectricity in a thin film of a novel material of nominal composition PbTi 0.5 Fe 0.5 O 3 - is probed by standard ferroelectric and ferromagnetic hysteresis loop measurements and by scanning probe microscopy of various kinds.Both magnetic domains and ferroelectric domains are observed in the same spatial region of the material, implying phase coexistence in this system. For both order parameters, sample morphology strongly affects roughness of the domain walls. PACS: 75.80.+q, 85.40, 68.64.Dz ________________________________________________________________ Recent resurgence of interest in multiferroic systems in general, and in magnetoelectric systems in particular, is driven by two different reasons, namely, the basic physics of coexistence of two order parameters in the ground state and the possibility of using this coexistence, and a possible coupling between them, for devising novel applications [1][2]. Magnetoelectric systems, which exhibit coexistence of magnetism and ferroelectricity with a possible coupling between the two order parameters, are of particular importance, especially when the magnetism is of the ferromagnetic variety. Multifunctional and exotic non-volatile memory applications are possible in that case. However, the presence of local spins and of off-centered structural distortion are basic requirements for magnetic and ferroelectric properties, respectively and naturally, these two seemingly unrelated phenomena rarely co-exist at room temperature. Unfortunately, most of the known multiferroic systems are antiferromegnetic with transition temperatures below room temperature [3,4]. Therefore, for device applications these materials hardly find any use.Recently, we have reported novel materials exhibiting magnetoelectric properties at room temperature [5][6][7]. In this letter we report room temperature multiferroic properties for lower compared to any of these phases. It is essential to reproduce these properties in thin films for their usefulness in practical applications, as well as for further basic physics investigations. In this letter we report that thin films of this material, grown on Pt/TiO 2 /SiO 2 /Si substrate by using Pulsed Laser Deposition (PLD) technique, preserve the room temperature multiferroic nature of this system. More importantly we are successful in demonstrating the phase coexistence occurring at microscopic scale as well.In order to achieve good chemical homogeneity and controlled stoichiometry, Pb(Ti 0.5 Fe 0.5 )O 3- powder sample was prepared by using wet chemical route (co-precipitation).The detailed procedure for synthesis is described elsewhere [7]. From Nominal composition (with Fe +3 replacing Ti +4 ) one would expect the system to be an electrical conductor. Instead, we have been able to synthesize samples, which are insulating. Powder samples thus prepared were compacted and sintered at 1000 C/2hr. to obtain dense target for the laser ablation process.Sintering was carried out in PbO atmosph...

We report the synthesis and optical characterization of semipolar-oriented III-nitride quantum well (QW) structures obtained by growth on chemical vapor deposited graphene layers using metalorganic vapor phase epitaxy. Various multi-quantum well stacks of GaN(QW)/AlGaN(barrier) and InGaN (QW)/GaN (barrier) were grown. Growth on graphene not only helps achieve a semipolar orientation but also allows facile transfer of the QW multilayer stack to other cheap, flexible substrates. We demonstrate room-temperature photoluminescence from layers transferred to flexible Kapton films.

We report that the major features in the temperature dependence of dc and ac magnetization of a well-known spin-chain compound, Ca 3 Co 2 O 6 , which has been known to exhibit two complex magnetic transitions due to geometrical frustration (one near 24 K and the other near 10 K), are found to be qualitatively unaffected in its nano materials synthesized by high-energy ballmilling. However, the multiple steps in isothermal magnetization -a topic of current interest in low-dimensional systems -known for the bulk form well below 10 K is absent in the nano particles. We believe that this finding will be useful to the understanding of the 'step' magnetization behavior of such spin-chain systems.