Divacancies and the hydrogenation of Mg-Ti films with short range chemical order

Leegwater, H.; Schut, H.; Egger, W.; Baldi, A.; Dam, B.; Eijt, S. W. H.
March 2010
Applied Physics Letters;3/22/2010, Vol. 96 Issue 12, p121902
Academic Journal
We obtained evidence for the partial chemical segregation of as-deposited and hydrogenated Mg1-yTiy films (0≤y≤0.30) into nanoscale Ti and Mg domains using positron Doppler-broadening. We exclusively monitor the hydrogenation of Mg domains, owing to the large difference in positron affinity for Mg and Ti. The electron momentum distribution broadens significantly upon transformation to the MgH2 phase over the whole compositional range. This reveals the similarity of the metal-insulator transition for rutile and fluorite MgH2. Positron lifetime studies show the presence of divacancies in the as-deposited and hydrogenated Mg-Ti metal films. In conjunction with the relatively large local lattice relaxations we deduce to be present in fluorite MgH2, these may be responsible for the fast hydrogen sorption kinetics in this MgH2 phase.


Related Articles

  • Strong tensile strain induced charge/orbital ordering in (001)-La7/8Sr1/8MnO3 thin film on 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3. Wang, J.; Hu, F. X.; Li, R. W.; Sun, J. R.; Shen, B. G. // Applied Physics Letters;2/1/2010, Vol. 96 Issue 5, p052501 

    The substrate-induced strain effect in La7/8Sr1/8MnO3 (LSMO) thin films grown on (001)-oriented SrTiO3 and ferroelectric 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN-PT) substrates was investigated. A metal-insulator transition was observed at low temperature in LSMO/PMN-PT, which was ascribed to...

  • Diodes with breakdown voltages enhanced by the metal-insulator transition of LaAlO3–SrTiO3 interfaces. Jany, R.; Breitschaft, M.; Hammerl, G.; Horsche, A.; Richter, C.; Paetel, S.; Mannhart, J.; Stucki, N.; Reyren, N.; Gariglio, S.; Zubko, P.; Caviglia, A. D.; Triscone, J.-M. // Applied Physics Letters;5/3/2010, Vol. 96 Issue 18, p183504 

    Using the metal-insulator transition that takes place as a function of carrier density at the LaAlO3–SrTiO3 interface, oxide diodes have been fabricated with room-temperature breakdown voltages of up to 200 V. With applied voltage, the capacitance of the diodes changes by a factor of 150....

  • First-principles study of pressure-induced metal-insulator transition in BiNiO3. Cai, M. Q.; Yang, G. W.; Tan, X.; Cao, Y. L.; Wang, L. L.; Hu, W. Y.; Wang, Y. G. // Applied Physics Letters;9/3/2007, Vol. 91 Issue 10, p101901 

    First-principles calculation is used to study the pressure-induced metal-insulator transition in BiNiO3. It is found that the G-antiferromagnetic insulator triclinic phase in BiNiO3 transforms to the ferromagnetic half-metallic orthorhombic phase with a volume collapse of 6.2% when the applied...

  • Multistep metal insulator transition in VO2 nanowires on Al2O3 (0001) substrates. Takami, Hidefumi; Kanki, Teruo; Tanaka, Hidekazu // Applied Physics Letters;1/13/2014, Vol. 104 Issue 2, p023104-1 

    We observed a temperature- and voltage-induced multistep metal-insulator transition (MIT) in vanadium dioxide nanowires fabricated on Al2O3 (0001) substrates. Nanowires with a width of 200 nm showed a multistep MIT that exhibited a resistivity change of nearly two orders of magnitude in a 0.5K...

  • Metal-insulator transition in double cobaltites RBaCo2O5.5 ( R = Eu, Gd): Specific features of their optical properties. Makhnev, A. A.; Nomerovannaya, L. V.; Strel'tsov, S. V.; Anisimov, V. I.; Barilo, S. N.; Shiryaev, S. V. // Physics of the Solid State;Mar2009, Vol. 51 Issue 3, p525 

    The temperature dependence of the optical properties of GdBaCo2O5.5 in the region of the metal-insulator transition was studied in the spectral range λ = 4.0–0.258 μm ( E = 0.3–4.8 eV) by the spectroscopic ellipsometry method. The electronic structure of the crystal at T =...

  • Manipulation of metal-insulator transition characteristics in aspect ratio-controlled VO2 micro-scale thin films on TiO2 (001) substrates. Ueda, Hiroki; Kanki, Teruo; Tanaka, Hidekazu // Applied Physics Letters;4/15/2013, Vol. 102 Issue 15, p153106 

    We manipulated the metal-insulator transition characteristics of VO2 thin films on TiO2 (001) substrates by changing their micro-scaled metallic domain configurations through size- and aspect ratio-control. A very steep resistance drop at 294 K was demonstrated for a 1D parallel domain...

  • Full configuration interaction study of the metal-insulator transition in model systems: LiN linear chains (N=2,4,6,8). Vetere, Valentina; Monari, Antonio; Bendazzoli, Gian Luigi; Evangelisti, Stefano; Paulus, Beate // Journal of Chemical Physics;1/14/2008, Vol. 128 Issue 2, p024701 

    The precursor of the metal-insulator transition is studied at ab initio level in linear chains of equally spaced lithium atoms. In particular, full configuration interaction calculations (up to 1×109 determinants) are performed, in order to take into account the different nature of the wave...

  • Metal–insulator transition: A plane mystery. Smet, Jurgen H. // Nature Physics;Jun2007, Vol. 3 Issue 6, p370 

    The article discusses the role of valley polarization in metal-insulator transition. According to the author, in two dimensions, any electron system approaching absolute zero should become insulating in theory. However, when an applied strain breaks this degeneracy the valleys become unequally...

  • Correlations between pressure and bandwidth effects in metal–insulator transitions in manganites. Congwu Cui, P.P.; Tyson, Trevor A. // Applied Physics Letters;2/9/2004, Vol. 84 Issue 6, p942 

    The effect of pressure on the metal–insulator transition in manganites with a broad range of bandwidths is investigated. A critical pressure is found at which the metal–insulator transition temperature, T[sub MI], reaches a maximum value in every sample studied. The origin of this...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics