A diode-pumped LPE-grown Yb:KYW planar waveguide laser is demonstrated in a microchip monolithic cavity configuration. Output powers as high as 148mW and thresholds as low as 40mW were demonstrated during continuous-wave operation. Pulses of 170ns duration with maximum pulse energy of 44nJ at a 722kHz repetition rate were generated when Q-switched using a semiconductor saturable absorber mirror.

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This work reviews some fundamental issues that are relevant for the fabrication of stable‐phase strontium ferromolybdate thin films. The main challenges for strontium ferromolybdate thin film deposition arise from the sensitivity of the material's magnetic properties to point defect formation: i) Antisite defect formation and oxygen nonstoichiometry should be avoided by precise composition control during film manufacturing; ii) a highly ordered state of the correct phase and B‐site cation valence will be obtained only in a very narrow window of growth conditions; iii) to avoid additional antisite disorder with decreasing synthesis temperature, the effective temperature at the film surface should be increased by an energy flux to the growing film surface. Since thin film deposition is nonequilibrium in nature, the review starts with the consideration of equilibrium phase stability. Cation and oxygen stoichiometries are analyzed with regard to their effect on key magnetic properties. Film strain formed due to thermal and lattice mismatch is of great concern since it influences the choice of the substrate. Finally, thin film deposition techniques are valued for their benefits in strontium ferromolybdate thin film technology.

Phone: þ351 234 378 117, Fax: þ351 234 378 197Nanosized single-phase powders of the ferrimagnetic double perovskite Sr 2 FeMoO 6-d (SFMO) with various degrees of the superstructural ordering of the Fe 3þ and Mo 5þ cations have been synthesized by the citrate-gel method at pH ¼ 4, 6, 9 (samples SFMO 4,6,and 9). According to the results of the X-ray photoelectron spectroscopy, a mixed valence state of the iron and molybdenum cations is realized in the obtained SFMO powders, whereby the concentration of Fe 2þ increases and that of Fe 3þ decreases with increasing pH. The charge state of iron and the redistribution of the electron density in SFMO has been studied by means of the M€ ossbauer spectroscopy. The charge disproportionation for the powders obtained at pH ¼ 6 and 9 facilitates the segregation of a-Fe. The temperature dependences of the magnetization measured in the field cooling and zero-field cooling regimes indicate the existence of superparamagnetism in the nanosized grains of SFMO 4, 6, and 9 at T < 19 K. The superparamagnetism is metastable up to a temperature Т S . The applied magnetic field stimulates the transition in nanosized grains from the metastable superparamagnetic state into the stable one, above some value of the magnetic field induction exceeding the minimal anisotropy field. 57Fe M€ ossbauer spectra taken at 20 K of Sr 2 FeMoO 6-d prepared at pH ¼ 6.

The present work reports on the new approach to create metal-supported Sr2FeMoO6 (SFMO)-based electrodes that have high potential to be applied in solid oxide fuel cells. The SFMO films were formed on stainless steel substrates by electrophoretic deposition (EPD) method. Ethyl alcohol with phosphate ester as a dispersant and isopropyl alcohol with I2-acetone mixture as a charge additive were considered as an effective medium for EPD of SFMO particles. The synthesis of SFMO powder as well as suspension preparation and deposition kinetics were systematically studied. The effect of applied voltage on the thickness and morphology of SFMO films was established. The microstructure of the deposits was examined by electron microscopy. The thickness, morphology and porosity of the SFMO layers can be fine-tuned by varying solvent, charging additives, deposition time, and applied voltage. According to X-ray photoelectron spectroscopy analysis, it was found that Fe(3+)-Mo(5+) and Fe(2+)-Mo(6+) pairs coexist, whereas the valent balance shifts toward an Fe(2+)-Mo(6+) configuration.

Double perovskites with the structural formula A2BB′O6±δ, especially the strontium ferromolybdate Sr2FeMoO6–δ, have attracted a lot of attention due to their unique magnetic and electrical properties and a possible application in spintronic devices. However, a strict correlation between the functional characteristics of Sr2FeMoO6–δ and its synthesis technology has been lacking up to date. Thus, we have studied in the present work the crystallization kinetics of Sr2FeMoO6–δ using reagents with different pre‐history as well as the structural and magnetic properties of the obtained compounds. Differences in the crystallization kinetics as well as higher magnetic inhomogeneity of Sr2FeMoO6–δ synthesised from a mixture of MoO3, Fe2O3, SrCO3 in comparison with the compound synthesised from the SrFeO2.5 and SrMoO4–y precursors have been found and interpreted. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Single‐phase Sr2FeMoO6−δ powders with various oxygen indices (δ) and degrees of the superstructural ordering (P) of the Fe/Mo cations are obtained from SrFeO2.52 and SrMoO4 reagents via solid‐state synthesis. It has been established by means of the X‐ray and neutron diffraction that, upon reducing the oxygen content and enhancing the superstructural ordering, the lengths of the Fe–O1 and Mo–O2 bonds in the crystal lattice increase, whereas the Fe–O2 and Mo–O1 bond lengths decrease. At the same time, the volume of the unit cell is reduced, which indicates an enhancement of the covalency degree of the bonds and stimulates a redistribution of the electron density, as well as an increase of the concentration of the spin‐down charge carriers located in the conduction band on the Mo(t2g)↓ orbitals. This circumstance leads to an increase of the density of states at the Fermi level, accompanied by an amplification of the exchange interaction and elevation of the Curie temperature, which points to the leading role of the spin‐polarized charge carriers at the Fermi level in the exchange interaction.

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