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In the present work, room temperature epitaxial growth of Zn-doped iron oxide films (Zn: FeO x ) was achieved by pulsed laser deposition, on c-cut sapphire substrates without any high temperature thermal treatments before the growth. The nature of the oxide phases (wüstite and/or spinel) present in the films depends on the oxygen pressure during the laser ablation. At the residual vacuum (2 × 10 − 7 mbar), the (111) wüstite (Zn: FeO) textures was obtained in the films, while oxygen pressures between 2 × 10 − 5 to 2 × 10 − 3 mbar led to the growth of the spinel (Zn: Fe 3 O 4 ) phase on the c-cut sapphire substrate. Moreover, the species emitted by the target in the 2 × 10 − 7 to 2 × 10 − 5 mbar range, preserve their high kinetic energy which allows an easy crystallization of the film on the substrate at room temperature, leading to the epitaxial growth of the wustite and spinel phases. Magnetic properties through M(H) curves at 10 K and 300 K, of the wüstite-based film grown under 2 × 10 − 7 mbar were studied, and an exchange bias due to the presence of Fe 3+ cation in the film is observed. Finally, the possible mechanisms of the room temperature epitaxial growth of the oxide films on the substrate are presented and discussed.

Bi 1.5− x Zn 0.92− y Nb 1.5 O 6.92− δ (BZN) thin films were grown by pulsed laser deposition on two different Pt-covered substrates, namely textured {111}Pt/TiO 2 /SiO 2 /(100)Si substrate (Pt/Si) and epitaxial {111}Pt/R-plane sapphire substrate (Pt/sapphire). In both cases, the BZN films present {111} and {100} out-of-plane orientations, in relative ratios of 65:35 on Pt/Si and 80:20 on Pt/sapphire, respectively. The film grown on Pt/Si is textured, while the film deposited on Pt/sapphire presents epitaxial-like relationships with the substrate, for both out-of-plane orientations. Dielectric measurements were taken on both types of thin films, using Pt/BZN/Pt planar capacitor structures. The BZN/Pt/sapphire film presents higher dielectric constant (245 at 100 kHz) and higher tunability (12% at 600 kV/cm) than the BZN/Pt/Si film (200; 6%), while the dielectric losses values are nearly same (~0.05).

K x Na 1− x NbO 3 thin films with x  = 0.5 and x  = 0.7 were deposited by pulsed laser deposition onto R-cut sapphire substrates to be suitable for microwave applications. The 500–800-nm-thick films present a preferential (100) orientation. The ω -scans show a weak mosaicity (full-width at half-maximum equal to 0.36° and 0.60° for x  = 0.5 and x  = 0.7, respectively). In addition to this texture, the in-plane ordering evidenced by X-ray diffraction φ -scan for the (100) orientation is in agreement with an epitaxial-like growth in spite of the high lattice mismatch between K x Na 1− x NbO 3 and sapphire. The dielectric characteristics and the frequency tunability at microwave frequencies were obtained from coplanar waveguide devices (transmission lines and stub resonators). For the K 0.5 Na 0.5 NbO 3 and K 0.7 Na 0.3 NbO 3 compositions, high dielectric permittivity ε r values of 360 and 250 and loss tangent tan δ values of 0.36 and 0.43 without biasing were retrieved from the transmission line measurements at 10 GHz, respectively. Frequency tunabilities of 15 and 12% have been assessed under 80 kV/cm biasing from stub resonator measurements for the K 0.5 Na 0.5 NbO 3 and K 0.7 Na 0.3 NbO 3 compositions, respectively. K 0.5 Na 0.5 NbO 3 composition is therefore a promising solution for miniaturized tunable devices at microwave frequencies.

K.sub.xNa.sub.1-xNbO.sub.3 thin films with x = 0.5 and x = 0.7 were deposited by pulsed laser deposition onto R-cut sapphire substrates to be suitable for microwave applications. The 500-800-nm-thick films present a preferential (100) orientation. The [omega]-scans show a weak mosaicity (full-width at half-maximum equal to 0.36° and 0.60° for x = 0.5 and x = 0.7, respectively). In addition to this texture, the in-plane ordering evidenced by X-ray diffraction [phi]-scan for the (100) orientation is in agreement with an epitaxial-like growth in spite of the high lattice mismatch between K.sub.xNa.sub.1-xNbO.sub.3 and sapphire. The dielectric characteristics and the frequency tunability at microwave frequencies were obtained from coplanar waveguide devices (transmission lines and stub resonators). For the K.sub.0.5Na.sub.0.5NbO.sub.3 and K.sub.0.7Na.sub.0.3NbO.sub.3 compositions, high dielectric permittivity [epsilon].sub.r values of 360 and 250 and loss tangent tan[delta] values of 0.36 and 0.43 without biasing were retrieved from the transmission line measurements at 10 GHz, respectively. Frequency tunabilities of 15 and 12% have been assessed under 80 kV/cm biasing from stub resonator measurements for the K.sub.0.5Na.sub.0.5NbO.sub.3 and K.sub.0.7Na.sub.0.3NbO.sub.3 compositions, respectively. K.sub.0.5Na.sub.0.5NbO.sub.3 composition is therefore a promising solution for miniaturized tunable devices at microwave frequencies.

KxNa1−xNbO3 thin films with x = 0.5 and x = 0.7 were deposited by pulsed laser deposition onto R-cut sapphire substrates to be suitable for microwave applications. The 500–800-nm-thick films present a preferential (100) orientation. The ω-scans show a weak mosaicity (full-width at half-maximum equal to 0.36° and 0.60° for x = 0.5 and x = 0.7, respectively). In addition to this texture, the in-plane ordering evidenced by X-ray diffraction φ-scan for the (100) orientation is in agreement with an epitaxial-like growth in spite of the high lattice mismatch between KxNa1−xNbO3 and sapphire. The dielectric characteristics and the frequency tunability at microwave frequencies were obtained from coplanar waveguide devices (transmission lines and stub resonators). For the K0.5Na0.5NbO3 and K0.7Na0.3NbO3 compositions, high dielectric permittivity εr values of 360 and 250 and loss tangent tanδ values of 0.36 and 0.43 without biasing were retrieved from the transmission line measurements at 10 GHz, respectively. Frequency tunabilities of 15 and 12% have been assessed under 80 kV/cm biasing from stub resonator measurements for the K0.5Na0.5NbO3 and K0.7Na0.3NbO3 compositions, respectively. K0.5Na0.5NbO3 composition is therefore a promising solution for miniaturized tunable devices at microwave frequencies.

Bi.sub.1.5-xZn.sub.0.92-yNb.sub.1.5O.sub.6.92-[delta] (BZN) thin films were grown by pulsed laser deposition on two different Pt-covered substrates, namely textured 111Pt/TiO.sub.2/SiO.sub.2/(100)Si substrate (Pt/Si) and epitaxial 111Pt/R-plane sapphire substrate (Pt/sapphire). In both cases, the BZN films present 111 and 100 out-of-plane orientations, in relative ratios of 65:35 on Pt/Si and 80:20 on Pt/sapphire, respectively. The film grown on Pt/Si is textured, while the film deposited on Pt/sapphire presents epitaxial-like relationships with the substrate, for both out-of-plane orientations. Dielectric measurements were taken on both types of thin films, using Pt/BZN/Pt planar capacitor structures. The BZN/Pt/sapphire film presents higher dielectric constant (245 at 100 kHz) and higher tunability (12% at 600 kV/cm) than the BZN/Pt/Si film (200; 6%), while the dielectric losses values are nearly same (~0.05).

The decrease of the growth temperature of platinum (Pt) thin film on silicon substrate was studied using Ca 2 Nb 3 O 10 nanosheets (CNOns) as seed layer. These nanosheets were obtained by the delamination of the layered perovskite KCa 2 Nb 3 O 10 and they were deposited on silicon substrates by the Langmuir–Blodgett method. Pt thin films were sputtered on silicon coated by CNOns (CNOns/SiO 2 /Si), and on TiO 2 /SiO 2 /Si substrates for comparison, at temperatures ranging from room temperature up to 625 °C. X-ray diffraction, scanning electron microscopy, and atomic force microscopy were used to characterize the crystalline quality, thickness, surface morphology and roughness of the Pt thin films. Highly (111) textured Pt thin films were obtained on CNOns/SiO 2 /Si at substrate temperature as low as 200 °C. The full width at half maximum of the rocking curve of the (111) X-ray peak was about one degree, indicating a high crystalline orientation. The resistivity was measured at room temperature by the four point probes method to confirm the quality of Pt thin films elaborated at low temperatures. These results pave the way for easier integration of highly textured platinum thin film in low temperature microelectronic processes.

This paper reports the preparation conditions and structure characteristics of Al–Cr–Fe very thin films (10–30 nm) obtained by the flash evaporation technique. The films are either amorphous or crystallized, depending on the thickness of the sample and temperature of the substrate. Annealing of amorphous films leads to crystallization of intermetallic phases that are all linked with quasicrystals. In particular, we have identified by transmission electron microscopy the following structures: body-centered-cubic (bcc) γ-brass phase, monoclinic λ–Al13(Cr,Fe)4 phase, and orthorhombic O1-phase, all of them already observed in this system, together with four new structures, i.e., a face-centered-cubic (fcc) γ-brass phase (superstructure of the bcc phase), monoclinic λ′-phase (related to the λ-phase) and two orthorhombic phases (1/1/; 1/1) and (1/0; 2/1) approximants of the decagonal phase). In this study, we point out the occurrence of twin defects of the λ–Al13(Cr,Fe)4 phase. Films prepared directly in the crystalline state comprise the O1 approximant. Electron energy loss spectroscopy measurements show that all films are not oxidized except for the presence of a native oxide layer that forms in ambient atmosphere with a thickness that cannot exceed 0.3 nm. Optical properties were investigated and show that films need to be large enough (>30 nm) to reproduce the properties of bulk alloys. Finally, contact angle wetting measurements reveal that the presence of such films on a substrate, even at very low thickness, considerably decreases the wetting behavior by water.

K ₓ Na₁₋ₓNbO₃ thin films with x = 0.5 and x = 0.7 were deposited by pulsed laser deposition onto R-cut sapphire substrates to be suitable for microwave applications. The 500–800-nm-thick films present a preferential (100) orientation. The ω-scans show a weak mosaicity (full-width at half-maximum equal to 0.36° and 0.60° for x = 0.5 and x = 0.7, respectively). In addition to this texture, the in-plane ordering evidenced by X-ray diffraction φ-scan for the (100) orientation is in agreement with an epitaxial-like growth in spite of the high lattice mismatch between K ₓ Na₁₋ₓNbO₃ and sapphire. The dielectric characteristics and the frequency tunability at microwave frequencies were obtained from coplanar waveguide devices (transmission lines and stub resonators). For the K₀.₅Na₀.₅NbO₃ and K₀.₇Na₀.₃NbO₃ compositions, high dielectric permittivity εᵣ values of 360 and 250 and loss tangent tanδ values of 0.36 and 0.43 without biasing were retrieved from the transmission line measurements at 10 GHz, respectively. Frequency tunabilities of 15 and 12% have been assessed under 80 kV/cm biasing from stub resonator measurements for the K₀.₅Na₀.₅NbO₃ and K₀.₇Na₀.₃NbO₃ compositions, respectively. K₀.₅Na₀.₅NbO₃ composition is therefore a promising solution for miniaturized tunable devices at microwave frequencies.

This paper reports the preparation conditions and structure characteristics of Al-Cr-Fe very thin films (10-30 nm) obtained by the flash evaporation technique. The films are either amorphous or crystallized, depending on the thickness of the sample and temperature of the substrate. Annealing of amorphous films leads to crystallization of intermetallic phases that are all linked with quasicrystals. In particular, we have identified by transmission electron microscopy the following structures: body-centered-cubic (bcc) *g-brass phase, monoclinic *l-Al13(Cr,Fe)4 phase, and orthorhombic O1-phase, all of them already observed in this system, together with four new structures, i.e., a face-centered-cubic (fcc) *g-brass phase (superstructure of the bcc phase), monoclinic X'-phase (related to the *l-phase) and two orthorhombic phases (1/1/; 1/1) and (1/0; 2/1) approximants of the decagonal phase). In this study, we point out the occurrence of twin defects of the *l-Al13(Cr,Fe)4 phase. Films prepared directly in the crystalline state comprise the O1 approximant. Electron energy loss spectroscopy measurements show that all films are not oxidized except for the presence of a native oxide layer that forms in ambient atmosphere with a thickness that cannot exceed 0.3 nm. Optical properties were investigated and show that films need to be large enough ( > 30 nm) to reproduce the properties of bulk alloys. Finally, contact angle wetting measurements reveal that the presence of such films on a substrate, even at very low thickness, considerably decreases the wetting behavior by water. Our aim in the present study was focused at the preparation of very thin films for optical applications.