Neodymium-Doped Sr-5(Po4)(3)F And Sr-5(Vo4)(3)F

Neodymium-doped Sr-5(PO4)(3)F [neodymium strontium fluoride phosphate, (Nd,Sr)(5)(PO4)(3)F] and neodymium-doped Sr-5(VO4)(3)F [neodymium strontium fluoride vanadate, (Nd,Sr)(5)(VO4)(3)F] crystallize in space group P6(3)/m and are isostructural with calcium fluorophosphate, Ca-5(PO4)(3)F. There are two different Sr sites in Sr-5(XO(4))(3)F, denoted Sr(1) and Sr(2). Using single-crystal X-ray diffraction the two structures were refined to R factors of 2.3 and 2.2%, respectively, showing that Nd is present at both Sr sites in (Sr,Nd)(5)(VO4)(3)F but only at the Sr(2) site in (Sr,Nd)(5)(PO4)(3)F

Irreversible Effects in LaGa1-xMnxO3

Quasi-irreversible increase in the electrical conductivity is observed in single crystals of LaGa1-xMnxO3. The effect lasts for long time at room temperature and can be erased by heating of the crystal above the phase transition temperature. We explain the observed effects in terms of ionization and local lattice distortion processes.Comment: 8 pages, 4 figure

Integration of epitaxial colossal magnetoresistive films onto Si(100) using SrTiO\u3csub\u3e3\u3c/sub\u3e as a template layer

We report on the integration of epitaxial colossal magnetoresistive La0.67Ba0.33MnO films on Si(100) semiconductor using SrTiO3 template layer by pulsed-laser deposition. X-ray diffraction reveals the superior quality of the manganite film that grows epitaxially on heteroepitaxially grown SrTiO3 template layer on Si substrate. The epitaxial films demonstrate remarkable surface morphology, magnetic transition and hysteresis, magnetoresistance, and ferromagnetic resonance, illustrating the ferromagnetic nature of the film and possible device applications at room temperature

Growth Of Laser-Quality Single-Crystals Of Nd-3+-Doped Calcium Fluorapatite And Their Efficient Lasing Performance

The Czochralski growth of laser-quality Nd3+-doped calcium fluorapatite single crystals and their lasing characterization are reported. Low threshold and high efficiency lasing performances were achieved in both continuous-wave and long pulse laser-pump-laser operation. The effect of concentration quenching on laser performance is discussed

Crystal growth, spectroscopic characterization, and laser performance of a new efficient laser material Nd:Ba-5(PO4)(3)F

High quality single crystals of neodymium doped barium fluorapatite have been grown by the Czochralski technique and evaluated as an optical gain medium. A product of the emission cross section and lifetime of Nd3+ luminescence of more than 1.8x10(-22) cm(2) s at 1055 nm, and laser performance with slope efficiency up to 65% have been obtained

Ytterbium-Doped Apatite-Structure Crystals: A New Class Of Laser Materials

A new class of Yb-lasers is summarized in this article. The apatite family of crystals, based on the hexagonal structure of the mineral fluorapatite, has been found to impose favorable spectroscopic and laser properties on the Yb3+ activator ion. Crystals of Yb-doped Ca5(PO4)3F, Sr5(PO4)3F, CaxSr5-x(PO4)3F, and Sr5(VO4)3F have been grown and investigated. Several useful laser crystals have been identified which offer a variety of fundamental laser parameters for designing diode-pumped systems. In general, this class of materials is characterized by high emission cross sections (3.6-13.1 X 10(-20) cm2), useful emission lifetimes (0.59-1.26 ms), a strong pump band (sigma(abs)=2.0-10.0 X 10(-20) cm2), and pump and extraction wavelengths near 900 and 1045 nm, respectively. Efficient lasing has been demonstrated for several of the members of this class of materials, and high optical quality crystals have been grown by the Czochralski method. A summary of the laser parameters and a discussion of the Yb:apatite class of lasers is presented

Growth Of High-Quality Single Crystals Of Fap (Ca5(Po4)3F) And Its Isomorphs

The Czochralski crystal growth of calcium fluorapatite Ca5(PO4)3F and calcium-strontium fluorapatite (Ca1-xSrx)5(PO4)3F is reported. The growth conditions for producing the rare earth and chromium doped crystals of high quality are presented. The influence of the replacement of some calcium for strontium in FAP on crystal quality and on spectroscopic properties is discussed

Growth And Characterization Of Pure Cr; Cr,Er And Cr,Ho Codoped Y2Sio5

The Czochralski crystal growth of pure Cr, Er and Ho doped as well as Cr,Er and Cr,Ho codoped yttrium silicate Y2SiO5 (YSO) is reported. The growth conditions for producing the inclusion free single crystals of high optical quality are discussed. Spectroscopic properties of the singly doped and codoped material at room temperature are compared. Energy transfer processes from Cr4+ ions to Ho3+ and Er3+ ions in YSO host have been demonstrated for the first time

Laser Demonstration Of Neodymium-Doped Strontium Chlorovanadate

Nd:Sr5(VO4)3Cl has been successfully lased using a Ti:sapphire pump laser operating at 810 nm. A slope efficiency of 52% for the 1.065 mum laser line and a lasing threshold of only a few tens of milliwatts have been measured. These favorable results are comparable to another Nd-doped vanadate apatite, Sr5(VO4)3F. A brief survey of the spectroscopy of Nd3+ in Sr5(VO4)3Cl, Sr5(VO4)3F, and Ca5(VO4)3F reveals properties which suggest the vanadate-based apatite crystals as a whole may represent a useful new class of Nd-laser hosts