Ferroelectric Ba x Sr 1-x TiO 3 (BSTO, x , 0.6) films were grown on various substrates (SrTiO 3 , LaAlO 3 , MgO, f -Al 2 O 3 , alumina, and Y 3 Fe 5 O 12 ) using RF sputtering. The results of complex BSTO diagnostics using medium energy ion scattering (MEIS) were compared with dielectric characteristics at 1 MHz and 30 GHz. The BSTO films were different on the MEIS yield h s characterizing film structure and temperature T m corresponded to maximal capacitance of BSTO varactor. Highly-oriented BSTO films of ∼ 500 nm thick grown on MgO and LaAlO 3 had T m = (150-230 K), tunability K = l (0)/ l ( E max ) , 1,3 m 1,5 ( E max , 10 V/ w m) and tan i h 10 m 3 . The films grown on sapphire, alumina and YIG substrates had less ordered structure, lower strains, T m = (250 - 260 K), K , 1,6 - 2,2 and tan i S 10 m 3 . The tan i of the investigated BSTO films at f , 30 GHz was higher by approximately one order of magnitude.

The temperature dependence of a capacitance of a planar capacitor based on Ba1−xSr1−xTiO3 (BSTO) films was investigated and some anomalies were observed. It was experimentally found that the barium concentration decreased across the film thickness in the direction from film/substrate interface to the film surface. The barium concentration, x, of BSTO films grown on sapphire (r-cut) substrates changed from x=0.52 on the film/substrate interface to x=0.3 on the film surface. The investigated films should be considered as a multiphase composition with different phase transition temperatures. The phenomenological model of dielectric response of the film structure has been suggested, which served as a basis for introducing an effective dielectric permittivity of the layered film.

Capacitance voltage and current voltage characteristics of BSTO ferroelectric films containing a manganese dioxide impurity (∼1.5–2 mol%) are compared to those of impurity-free samples. It is shown that in Mn-doped samples tan δ drops to 10−3, and the dependence of tan δ on the applied voltage changes as well. IVCs of these samples are strictly ohmic and do not show a nonlinearity at high voltages. A mechanism is proposed of the effect of Mn on the charge state of the defects comprising oxygen vacancies in BSTO films.

The propagation of magnetostatic waves at the interface between an yttrium-iron-garnet (YIG) film and a layer of perovskite compound LaAlO3, SrTiO3, or YBa2Cu3O7−x (YBCO) was experimentally studied. The microwave dispersion characteristics were measured at room temperature and at 77 K. An effective method for controlling the propagation speed and the phaseshift of magnetostatic waves in the YIG/YBCO structures is suggested. Specifically, the phaseshift at 3 GHz is changed by more than 1.5π by reducing the critical current density from 1 to 0.7× 106 A/cm2.

The effect of the ratios of the cationic components and internal strains on the critical temperature T c and the dielectric characteristics of BSTO ferroelectric films grown on α-Al2O3 [1012] and LaAlO3 substrates were investigated. Ion backscattering diagnostics revealed a barium deficiency in the surface layer of the films and showed that the films differ in structural quality.