共查询到20条相似文献,搜索用时 0 毫秒
1.
S. Vatnik M. C. Pujol J. J. Carvajal X. Mateos M. Aguiló F. Díaz V. Petrov 《Applied physics. B, Lasers and optics》2009,95(4):653-656
The three thermo-optic coefficients of the biaxial laser host KLu(WO4)2 are measured at 633 nm by a deflection method. Their values at 300 K amount to ∂
n
g
/∂
T=−7.4×10−6 K−1; ∂
n
m
/∂
T=−1.6×10−6 K−1 and ∂
n
p
/∂
T=−10.8×10−6 K−1. Nearly athermal propagation directions are found for polarizations along the N
m
and N
p
dielectric axes. 相似文献
2.
F. Guo J. Ru H. Li N. Zhuang B. Zhao J. Chen 《Applied physics. B, Lasers and optics》2009,94(3):437-441
Lithium terbium molybdate (LiTb(MoO4)2) single crystal was grown by the Czochralski method. The lattice parameters of the crystal were determined by X-ray diffraction
analysis. The absorption coefficient and the Faraday rotation spectrum (B=1.07 T) were investigated at wavelengths of 400–1500 nm at room temperature. Verdet constants of LiTb(MoO4)2 crystal at 532-, 633- and 1064-nm wavelengths were measured by the extinction method. The results show that LiTb(MoO4)2 crystal has a larger magneto-optical figure of merit than that of terbium gallium garnet at wavelengths of 600–1500 nm. 相似文献
3.
D. Do S. S. Kim S. W. Yi J. W. Kim 《Applied Physics A: Materials Science & Processing》2009,94(3):697-701
Ferroelectric and dielectric properties of bilayered ferroelectric thin films, SrBi4Ti4O15 grown on Bi4Ti3O12, were investigated. The thin films were annealed at 700°C under oxygen atmosphere. The bilayered thin films were prepared
on a Pt(111)/Ti/SiO2/Si substrate by a chemical solution deposition method. The dielectric constant and dielectric loss of the bilayered thin
films were 645 and 0.09, respectively, at 100 kHz. The value of remnant polarization (2P
r) measured from the ferroelectric thin film capacitors was 60.5 μC/cm2 at electric field of 200 kV/cm. The remnant polarization was reduced by 22% of the initial value after 1010 switching cycles. The results showed that the ferroelectric and dielectric properties of the SrBi4Ti4O15 on Bi4Ti3O12 ferroelectric thin films were better than those of the SrBi4Ti4O15 grown on a Pt-coated Si substrate suggesting that the improved properties may be due to the different nucleation and growth
kinetics of SrBi4Ti4O15 on the c-axis-oriented Bi4Ti3O12 layer or on the Pt-coated Si substrate. 相似文献
4.
L. Kovács M. Mazzera E. Beregi R. Capelletti 《Applied physics. B, Lasers and optics》2009,94(2):273-277
Several weak absorption bands have been observed in the optical absorption spectra of pure and rare-earth-doped YAl3(BO3)4 single crystals in the 3350– 3650 cm−1 wave number region. Two of them, peaking at about 3377 cm−1 and 3580 cm−1 in the 8 K spectra, appear in most of the samples. They are tentatively attributed to the stretching mode of OH− ions incorporated in the crystal during the growth. An additional absorption band at about 5250 cm−1 at 8 K has also been detected in almost all samples. The temperature and polarization dependences of these bands, and their
possible origin, are discussed. 相似文献
5.
M. Aoki K. Miwa T. Noritake N. Ohba M. Matsumoto H.-W. Li Y. Nakamori S. Towata S. Orimo 《Applied Physics A: Materials Science & Processing》2008,92(3):601-605
We have investigated the structural and dehydriding properties of Ca(BH4)2. It was found that Ca(BH4)2 undergoes a structural phase transformation from an orthorhombic low-temperature (LT) modification into a tetragonal high-temperature
(HT) modification between 433 K and 523 K. The amount of hydrogen desorbed from Ca(BH4)2 during the pressure–composition (p–c) isotherm measurement was 5.9 mass%. This hydrogen desorption is caused by the partial dehydrogenation of Ca(BH4)2 accompanied by the formation of CaH2 and orthorhombic intermediate phases. 相似文献
6.
S. Rivier U. Griebner V. Petrov H. Zhang J. Li J. Wang J. Liu 《Applied physics. B, Lasers and optics》2008,93(4):753-757
Passive mode locking of the self-frequency doubling Yb:YAB crystal with a saturable absorber mirror is studied at the fundamental
wavelength. This laser has a very low threshold, and pulses as short as 85 and 87 fs are obtained for Ti:sapphire and diode
laser pumping, respectively. 相似文献
7.
Takehito Yoshida Hirokazu Toyoyama Ikurou Umezu Akira Sugimura 《Applied Physics A: Materials Science & Processing》2008,93(4):961-966
Nanostructured Ni-doped indium–tantalum–oxides (InTaO4) were synthesized by a reactive pulsed laser ablation process, aiming at the final goal of direct splitting of water under
visible sunbeam irradiation. The third harmonics beam of a Nd:YAG laser was focused onto a sintered In0.9Ni0.1TaO4−δ
target in pure oxygen background gases (0.05–1.00 Torr). Increasing the oxygen gas pressure, via thin films having nanometer-sized
strong morphologies, single-crystalline nanoparticles were synthesized in the reactive vapor phases. The nanostructured deposited
materials have the monoclinic layered wolframite-type structure of bulk InTaO4, without oxygen deficiency. 相似文献
8.
N. Coluccelli G. Galzerano L. Bonelli A. Toncelli A. Di Lieto M. Tonelli P. Laporta 《Applied physics. B, Lasers and optics》2008,92(4):519-523
We present a comparative analysis on the growth, the spectroscopic features, and the cw laser action of room-temperature Yb(5%):LiYF4 (YLF) and Yb(10%):KYF4 (KYF) crystals. Optical slope efficiencies of 33% and 52% have been demonstrated for Yb:YLF and Yb:KYF crystals, respectively.
A remarkable wide wavelength tunability from 1.01 to 1.07 μm has been obtained for both laser crystals. 相似文献
9.
M. Kodu T. Avarmaa H. Mändar R. Jaaniso 《Applied Physics A: Materials Science & Processing》2008,93(3):801-805
This paper reports the first results obtained on monobarium gallate thin films grown on silicon and platinum coated substrates
by pulsed laser deposition. The influence of oxygen background pressure and substrate (or post-annealing) temperature on the
film properties was studied. The films were characterized by XRD, RHEED, AFM, photoelectron and electrical impedance spectroscopy.
The structure analysis showed that the films crystallized into a hexagonal phase, most probably into (metastable) α-BaGa2O4. Depending on deposition conditions, films with different (from nearly epitaxial to polycrystalline) textures were obtained. 相似文献
10.
The absorption spectra, fluorescence spectrum and fluorescence decay curve of Nd3+ ions in CaNb2O6 crystal were measured at room temperature. The peak absorption cross section was calculated to be 6.202×10−20 cm2 with a broad FWHM of 7 nm at 808 nm for E//a light polarization. The spectroscopic parameters of Nd3+ ions in CaNb2O6 crystal have been investigated based on Judd-Ofelt theory. The parameters of the line strengths Ω
t
are Ω
2=5.321×10−20 cm2,Ω
4=1.734×10−20 cm2,Ω
6=2.889×10−20 cm2. The radiative lifetime, the fluorescence lifetime and the quantum efficiency are 167 μs, 152 μs and 91%, respectively. The fluorescence branch ratios are calculated to be β
1=36.03%,β
2=52.29%,β
3=11.15%,β
4=0.533%. The emission cross section at 1062 nm is 9.87×10−20 cm2. 相似文献
11.
M. S. B. Darby T. C. May-Smith R. W. Eason 《Applied Physics A: Materials Science & Processing》2008,93(2):477-481
We have demonstrated pulsed laser deposition of Nd-doped gadolinium gallium garnet on Y3Al5O12 by the simultaneous ablation of two separate targets of Nd:Gd3Ga5O12 (GGG) and Ga2O3. Such an approach is of interest as a method of achieving stoichiometry control over films whilst the growth parameters are
kept constant and optimal for high quality crystal growth. We show here how the stoichiometry and resultant lattice parameter
of a film can be controlled by changing the relative deposition rates from the two targets. Films have been grown with enough
extra Ga to compensate for the deficiency that commonly occurs when depositing only from a GGG target. We have also grown
crystalline GGG films with an enriched Ga concentration, and this unconventional approach to film stoichiometry control may
have potential applications in the fabrication of films with advanced compositionally graded structures. 相似文献
12.
Z.-S. Liu 《Applied Physics A: Materials Science & Processing》2009,95(2):443-445
In a rare-earth antiferromagnet, two neighboring magnetic ions order spontaneously in opposite directions below the Néel temperature.
Especially when it is placed in an external magnetic field, the two magnetic ions react to the field in different ways, so
that they usually have different magnitudes and orientations below the magnetic transition temperature. Therefore, to describe
the magnetic structure of an antiferromagnet, the single-ion ferromagnetic-like model is inadequate. To solve this problem,
a two-ion model for rare-earth antiferromagnets is proposed and used in this work to investigate the magnetic properties of
DyNi2B2C. The magnetic susceptibility curves obtained with this model show good agreements with experimental data. 相似文献
13.
Al<Subscript>2</Subscript>O<Subscript>3</Subscript> plasma production during pulsed laser deposition
F. Caridi L. Torrisi A. M. Mezzasalma G. Mondio A. Borrielli 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):467-472
A Nd:YAG laser operating in second harmonic (532 nm), 3 ns pulse duration, 150 mJ pulse energy, and 10 Hz repetition rate,
is employed to irradiate Al2O3 target placed in high vacuum. The produced plasma is investigated by an ion collector used in time-of-flight configuration
and by a mass quadrupole spectrometer, in order to determine the equivalent plasma temperature and the atomic and molecular
composition. Pulsed laser deposition technique has been used to produce thin films on different substrates placed close to
the target. Different surface analyses, such as energy dispersive X-ray fluorescence (EDXRF), X-ray photoelectron spectroscopy
(XPS) and surface profilometry are employed to characterize the produced films. Measurements of ablation yield, plasma equivalent
temperature, acceleration voltage and characterization of grown thin films are presented and discussed. 相似文献
14.
B. H. Yanga P. C. Stancil 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(3):317-324
Quantum close-coupling and coupled-state approximation scattering calculations for rotational energy transfer of rotationally
excited CH4 due to collisions with He are presented for collision energies between 10−7 and 3000 cm−1 using the MP4 potential of Calderoni et al. [J. Chem. Phys. 121, 8261 (2004)]. State-to-state cross sections and rate coefficients
from selected initial rotational states of CH4 in symmetries A, E, and F are studied from the ultra-cold to the thermal regime. Comparison of the cross sections with available theoretical results
and experimental data show good agreement. Applications to astrophysics and cold laboratory environments are briefly addressed. 相似文献
15.
A.-S. Rüetschi D. Jaccard 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(1):43-49
High pressure resistivity measurements of the organic compound (TMTTF)2BF4 have been performed in a newly developped Bridgman cell providing good pressure conditions on a wide pressure range. For
the first time in this compound a zero resistance superconducting state is observed between 3 and 4 GPa. At temperatures above
the superconducting transition, the resistivities of the two high quality samples show a different behavior. One sample, provides
indications for a magnetic quantum critical point at the maximum of Tc, whereas in the other antiferromagnetic spin-fluctuations are present above Tc. 相似文献
16.
L. S. Ewe I. Hamadneh H. Salama N. A. Hamid S. A. Halim R. Abd-Shukor 《Applied Physics A: Materials Science & Processing》2009,95(2):457-463
The magnetotransport and magnetoresistive (MR) properties of manganese-based La0.67Ca0.33MnO3 perovskite with different grain sizes are reported. The electrical resistivity was measured as a function of temperature
in magnetic fields of 0.5 and 1 T. The insulator–metal transition temperature, T
IM, shifted to a higher temperature with the application of the magnetic field. In zero field, T
IM is almost constant (∼271 K) for all samples except for the sample with the largest grain size, where T
IM=265 K. The temperature dependence of resistivity was fitted with several equations in the metallic (ferromagnetic) region
and the insulating (paramagnetic) region. The density of states at the Fermi level, N(E
F), and the activation energy of electron hopping were estimated by fitting the resistivity versus temperature curves. The
ρ–T
2 curves are nearly linear in the metallic regime, but the ρ–T
2.5 curves exhibit a deviation from linearity. The variable range hopping model and small polaron hopping model fit the data
well in the high-temperature region, indicating the existence of the Jahn–Teller distortion that localizes the charge carriers.
MR was found to increase with an increase in the magnetic field, an effect which is attributed to the intergrain spin tunneling
effect. 相似文献
17.
M. van Leeuwen 《The European Physical Journal C - Particles and Fields》2009,61(4):569-574
We present selected recent results of multi-hadron correlation measurements in azimuth and pseudorapidity at intermediate
and high p
T
in Au+Au collisions at
, from the STAR experiment at RHIC. At intermediate p
T
, measurements are presented that attempt to determine the origin of the associated near-side (small Δφ) yield at large pseudo-rapidity difference Δη that is found to be present in heavy ion collisions. In addition, results are reported on new multi-hadron correlation measures
at high-p
T
that use di-hadron triggers and multi-hadron cluster triggers with the goal to constrain the underlying jet kinematics better
than in the existing measurements of inclusive spectra and di-hadron correlations. 相似文献
18.
Microstructures and impedance characteristics of chemical-solution-derived Bi3.15Nd0.85Ti3O12 thin films were studied as functions of temperature. A dielectric anomaly was found at around 450°C, corresponding to the
paraelectric to ferroelectric transition. Via complex impedance studies, grain and grain boundary contributions to the impedance
were separated. The resistance of grain and grain boundaries is found governed by the same kind of space charge with an activation
energy around 1.1 eV, close to that of oxygen vacancies in perovskite ferroelectrics. The low temperature ac conductance of
BNdT thin films shows a frequency dispersion, which can also be ascribed to space charges mainly due to oxygen vacancies.
The results were compared with SrBi2Ta2O9 in terms of oxygen vacancy conductivity. 相似文献
19.
Francis Leonard Deepak Alvaro Mayoral Miguel Jose Yacaman 《Applied Physics A: Materials Science & Processing》2009,96(4):861-867
The structural transformation of MoO3 nanobelts into MoS2 nanotubes using a simple sulfur source has been reported. This transformation has been extensively investigated using electron
microscopic and spectroscopic techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM),
high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), and energy-dispersive X-ray analysis
(SEM-EDAX and TEM-EDX). The method described in this report will serve as a generic route for the transformation of other
oxide nanostructures into the chalcogenide nanostructures. 相似文献
20.
We report on the fabrication and characterization of planar and channel waveguides in KTiOPO4 crystals by 6.0 MeV C3+ ion implantation with the dose of 1×1014 ions/cm2. The dark mode spectroscopy of the planar waveguide was measured using a prism coupling arrangement. An increase of the both
n
x
and n
y
refractive indices induced by the annealing after implantation is believed to be responsible for waveguide formation. The
bright near-field intensity distribution of the transverse-electric and transverse-magnetic modes in the annealed channel
waveguide was collected and studied by end-coupling method. 相似文献