Dielectric Properties of PbTiO₃Thin Films on CeO₂/Si(100) and Y₂O₃/Si(100)

Abstract

Recent developments in the modelling of the dark matter distribution in our Galaxy point out the necessity to consider some physical processes to satisfy observational data. In particular, models with adiabatic compression, which include the effect of the baryonic gas in the halo, increase significantly the dark matter density in the central region of the Milky Way. On the other hand, the non-universality in the scalar and gaugino sectors of supergravity models can also increase significantly the neutralino annihilation cross section. We show that the combination of both effects gives rise to a gammaray flux arising from the galactic centre largely reachable by future experiments like GLAST. JCAP01(2006)010Adiabatic compression and indirect detection of supersymmetric dark matter has been carried out imposing the most recent experimental constraints, such as the lower bound on the Higgs mass, the b → sγ branching ratio, and the muon g − 2. In addition, the recently improved upper bound on B(B s → µ + µ − ) has also been taken into account. The astrophysical (WMAP) bounds on the dark matter density have also been imposed on the theoretical computation of the relic neutralino density through thermal production.Keywords: dark matter, high energy photons, cosmology of theories beyond the SM, structure of galaxies ArXiv ePrint: hep-ph/0506204 Journal of Cosmology and Astroparticle Physics 01 (2006) 010 (stacks.iop.org/JCAP/2006/i=01/a=010) Journal of Cosmology and Astroparticle Physics 01 (2006) 010 (stacks.iop.org/JCAP/2006/i=01/a=010) Journal of Cosmology and Astroparticle Physics 01 (2006) 010 (stacks.iop.org/JCAP/2006/i=01/a=010) 8 For analytical derivations see e.g. the recent work [42], and references therein. 9 It is worth noticing that we obtain the same order of magnitude as the authors of [48]. Journal of Cosmology and Astroparticle Physics 01 (2006) 010 (stacks.iop.org/JCAP/2006/i=01/a=010) 12 Although alternative explanations for this result have been proposed modifying conveniently the standard theory of galactic gamma-ray [61], these turn out to be also controversial [62]. 13 See also [29] for a general analysis. Journal of Cosmology and Astroparticle Physics 01 (2006) 010 (stacks.iop.org/JCAP/2006/i=01/a=010)

Epitaxial ferroelectric interfacial devices

“…Various deposition methods, such as MBE, PLD, chemical vapor deposition (CVD), and sputtering, have been exploited to achieve highquality epitaxial thin films. [285][286][287][288][289] The majority of these studies employ [001]-oriented SrTiO 3 substrates. On SrTiO 3 (001), PbTiO 3 adatoms exhibit ideal 2D layer-by-layer growth 290 or even step-flow growth 291 to form atomically flat surfaces and interfaces.…”

Investigation of Pt/Si/CeO2/Pt MOS Device Structure by Impedance Spectroscopy

“…From the standpoint of serving as the dielectric in MOS structures, ceria's high dielectric constant (ε r ≈ 25) allows for the growth of significantly thicker films than that required for SiO 2 . Lastly, CeO 2 thin films are effective as buffer layers and diffusion barriers between the Si substrate and many complex and chemically reactive compounds, such as Pb(Zr,Ti)O 3 and PbTiO 3 [8][9][10].…”

Deposition of CeO2 Films on Si(100) Substrates by Electron Beam Evaporation

“…By increasing oxygen pressure, both the CeO 2 (111) and CeO 2 (200) peaks were observed, which can be explained as follows: The CeO 2 (111) plane has cerium and oxygen atoms together while the CeO 2 (200) planes have Ce atoms only. The substrate is more easily oxidized at higher O 2 pressure, and the CeO 2 (200) plane with only Ce atoms is more easily deposited on the substrate, due to the tendency of Ce atoms to combine with oxygen atoms 11–14…”