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19 Aug 1996

Volume 69, Issue 8, pp. 1023-1171

Page 2 of 2 Pages Previous Page | Jump to Page

Kinetics of epitaxial Si1−xGex growth using SiH2Cl2–GeH4–H2 mixture in reduced‐pressure chemical vapor deposition

S. Ito, T. Nakamura, and S. Nishikawa

Appl. Phys. Lett. 69, 1098 (1996); http://dx.doi.org/10.1063/1.117070 (3 pages) | Cited 5 times

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The dependences of the Ge/Si ratio in epitaxial Si1−xGex layers grown using a SiH2Cl2–GeH4–H2 mixture by reduced‐pressure chemical vapor deposition on the flow rate ratio of GeH4/SiH2Cl2 and on the total flow rate have been examined in the temperature range from 480 to 600 °C. As previously reported, the Ge/Si ratio does not increase linearly with the flow rate ratio; instead, the rate of increase decreases at high flow rate ratios. Additionally, it increases with increasing total flow rate when the ratio of GeH4/SiH2Cl2 is fixed. It is found that these flow rate dependences are well accounted for by assuming that the reaction order for SiH2Cl2 adsorption is twice as large as that for GeH4 adsorption. © 1996 American Institute of Physics.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
85.30.Pq Bipolar transistors

Photoexcited carrier dynamics in InAlGaAs/InP quantum well laser structures

S. Marcinkevičius, H. Hillmer, R. Lösch, and U. Olin

Appl. Phys. Lett. 69, 1101 (1996); http://dx.doi.org/10.1063/1.117071 (3 pages) | Cited 1 time

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Experimental investigations of carrier transport and capture into quantum wells are performed for InAlGaAs/InP laser structures. Time‐resolved photoluminescence measurements are made by upconversion technique. The characteristic times for the ambipolar carrier transport in the confinement region and the electron capture into the quantum wells are about 2–5 and 1 ps, respectively. The obtained results show a good potential for high‐speed InAlGaAs/InP quantum well lasers operating in the 1.5 μm spectral region. © 1996 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
78.66.Fd III-V semiconductors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
78.47.-p Spectroscopy of solid state dynamics

Self‐consistent modeling of accumulation layers and tunneling currents through very thin oxides

Farhan Rana, Sandip Tiwari, and D. A. Buchanan

Appl. Phys. Lett. 69, 1104 (1996); http://dx.doi.org/10.1063/1.117072 (3 pages) | Cited 86 times

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Poisson and Schrödinger equations are solved self‐consistently for accumulated layers in metal‐oxide‐semiconductor devices and applied to the calculation of tunneling currents at 300 K and 77 K and extraction of parameters for very thin oxides. Calculations at 300 K show strong agreement with measured tunneling currents and also point out the sources of inaccuracies in extracting thicknesses of oxides by electrical methods such as through measurement of capacitance. Direct tunneling current in thin oxides (1.5–2.0 nm) are shown to achieve larger than 1  A /cm2 current density for applied voltages smaller than 3 V, pointing to possibilities of achieving high endurance injection across thin oxides. Comparison of calculations using a classical approach and self‐consistent approach shows fortuitous agreements in tunneling currents despite large differences in the physical models. Appropriate methods for calculating tunneling currents from bound and extended quantum states are also described. © 1996 American Institute of Physics.
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85.30.De Semiconductor-device characterization, design, and modeling
85.30.Tv Field effect devices
73.40.Gk Tunneling

Electronic diffusivity measurement in silicon by photothermal microscopy

Benoît C. Forget, Isabelle Barbereau, Danièle Fournier, Suneet Tuli, and Amalendu B. Battacharyya

Appl. Phys. Lett. 69, 1107 (1996); http://dx.doi.org/10.1063/1.117073 (3 pages) | Cited 18 times

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In this letter we demonstrate that a photothermal microscopy experiment can be used to determine the electronic diffusivity (or carrier mobility) in the same way it is now widely used to measure locally thermal diffusivity of various nonsemiconductor materials. The main difficulty lies in the fact that in order to separate thermal and carrier diffusion, the experiment must be performed for a relatively large distance between the pump and probe beams. Photothermal signals are therefore rather weak and great experimental care must be taken. We present and discuss experimental results on Si. © 1996 American Institute of Physics.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
85.30.De Semiconductor-device characterization, design, and modeling
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects

Surface morphology of homoepitaxial silicon thin films grown using energetic supersonic jets of disilane

K. A. Pacheco, B. A. Ferguson, S. Banerjee, and C. B. Mullins

Appl. Phys. Lett. 69, 1110 (1996); http://dx.doi.org/10.1063/1.117074 (3 pages) | Cited 4 times

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The effect of different chemical mechanisms for adsorption, which depend on the incidence energy of disilane, on the film morphology is investigated by comparing deposition by high (∼2 eV) kinetic energy disilane jets, direct chemisorption; low (∼0.09 eV) kinetic energy disilane jets and ultra high vacuum chemical vapor deposition, trapping‐mediated chemisorption. For substrate temperatures of 500–550 °C the mechanism for adsorption does not influence the film morphology as observed for films up to 3300 Å thick, which are comparable in smoothness to the starting substrate, as determined by atomic force microscopy. © 1996 American Institute of Physics.
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68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Formation of semi‐insulating 6H‐SiC layers by vanadium ion implantations

T. Kimoto, T. Nakajima, H. Matsunami, T. Nakata, and M. Inoue

Appl. Phys. Lett. 69, 1113 (1996); http://dx.doi.org/10.1063/1.117075 (3 pages) | Cited 22 times

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Vanadium ion (V+) implantation has been successfully applied to the formation of semiinsulating 6H‐SiC layers. The resistivity of V+‐implanted layers strongly depended on the conduction type of initial 6H‐SiC crystals. The resistivity at room temperature exceeded 1012 Ω cm and 106 Ω cm for p‐ and n‐type samples, respectively. Compensation mechanism is discussed based on the temperature dependence of resistivity. This technique will be useful for device isolation, edge termination, and reduction of parasitic impedance of SiC devices. © 1996 American Institute of Physics.
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61.72.up Other materials
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.40.Ry Impurity doping, diffusion and ion implantation technology

Quenching of the spontaneous current oscillations in GaAs/AlAs superlattices under domain formation

Yaohui Zhang, Robert Klann, Klaus H. Ploog, and Holger T. Grahn

Appl. Phys. Lett. 69, 1116 (1996); http://dx.doi.org/10.1063/1.117076 (3 pages) | Cited 11 times

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Self‐sustained current oscillations in a dc biased GaAs/AlAs superlattice exhibiting domain formation can be quenched by applying an external ac driving voltage with a large amplitude. The frequency of the driving voltage has to be much larger than the oscillation frequency and the well‐to‐well hopping frequency of the domain boundary. Under this condition, the oscillations of the domain boundary cannot follow anymore the ac driving signal. Consequently, for a fixed dc bias voltage the accumulated charge forming the domain boundary is confined within a single quantum well resulting in stationary domains. © 1996 American Institute of Physics.
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73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Fq High-field and nonlinear effects
73.61.Ey III-V semiconductors

Inductively coupled plasma etching of GaN

R. J. Shul, G. B. McClellan, S. A. Casalnuovo, D. J. Rieger, S. J. Pearton, C. Constantine, C. Barratt, R. F. Karlicek, C. Tran, and M. Schurman

Appl. Phys. Lett. 69, 1119 (1996); http://dx.doi.org/10.1063/1.117077 (3 pages) | Cited 77 times

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Inductively coupled plasma (ICP) etch rates for GaN are reported as a function of plasma pressure, plasma chemistry, rf power, and ICP power. Using a Cl2/H2/Ar plasma chemistry, GaN etch rates as high as 6875 Å/min are reported. The GaN surface morphology remains smooth over a wide range of plasma conditions as quantified using atomic force microscopy. Several etch conditions yield highly anisotropic profiles with smooth sidewalls. These results have direct application to the fabrication of group‐III nitride etched laser facets. © 1996 American Institute of Physics.
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85.40.Hp Lithography, masks and pattern transfer
81.65.Cf Surface cleaning, etching, patterning
42.82.Cr Fabrication techniques; lithography, pattern transfer
81.05.Ea III-V semiconductors

Direct observation of hydrogen‐related luminescent states in subsurface region of homoepitaxial diamond films

Kazushi Hayashi, Hideyuki Watanabe, Sadanori Yamanaka, Hideyo Okushi, Koji Kajimura, and Takashi Sekiguchi

Appl. Phys. Lett. 69, 1122 (1996); http://dx.doi.org/10.1063/1.117078 (3 pages) | Cited 10 times

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We found hydrogen‐related luminescence in the subsurface region of chemical vapor deposited homoepitaxial diamond films by means of cathodoluminescence. A specific broad peak at around 540 nm is observed in the hydrogenated films, but not in the conventional oxidized films. The gap states related to the peak observed at around 540 nm are found to exist spatially in the surface region. The fact is consistent with the hydrogen distribution previously determined by secondary ion mass spectroscopy. The result indicates the existence of hydrogen‐related luminescent states in the subsurface region of as‐deposited homoepitaxial diamond films. © 1996 American Institute of Physics.
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78.60.Hk Cathodoluminescence, ionoluminescence
78.66.Li Other semiconductors
71.55.Cn Elemental semiconductors

Self‐induced persistent photoconductivity in resonant tunneling devices

B. R. A. Neves, E. S. Alves, J. F. Sampaio, A. G. de Oliveira, and M. V. B. Moreira

Appl. Phys. Lett. 69, 1125 (1996); http://dx.doi.org/10.1063/1.117079 (3 pages) | Cited 1 time

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We report on the observation of a novel effect in resonant tunneling devices (RTD): a self‐induced persistent photoconductivity (SIPPC). The SIPPC manifests itself as a permanent shift of the resonant peak position to lower voltages, which is induced by the RTD itself and not by external sources. The SIPPC is due to the presence of DX centers in the device, which are ionized by light generated in the device itself through the recombination of electron‐hole pairs created by impact ionization of hot electrons in the depletion layer of the device. © 1996 American Institute of Physics.
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73.40.Gk Tunneling
73.50.Pz Photoconduction and photovoltaic effects
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

Correlation between two dielectric breakdown mechanisms in ultra‐thin gate oxides

Hideki Satake, Naoki Yasuda, Shin‐ichi Takagi, and Akira Toriumi

Appl. Phys. Lett. 69, 1128 (1996); http://dx.doi.org/10.1063/1.117080 (3 pages) | Cited 23 times

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The origin of stressing polarity dependence of charge‐to‐breakdown, Qbd, in thin SiO2 is discussed based on the temperature dependence of Qbd for both stressing polarities using wet and dry oxides. It was found that the temperature dependence of Qbd, which increases with decreasing temperature in the high temperature region and tends to saturate in the low temperature region, is identical irrespective of the stressing polarity and the oxidation condition. It has been proposed that the strain gradient from Si/SiO2 interface to SiO2/gate electrode interface determines directly both the Si–H bond density which dominates Qbd in high temperature region and the strained Si–O bond density which dominates Qbd in the low temperature region, irrespective of gate polarity and of oxidation condition. © 1996 American Institute of Physics.
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77.55.-g Dielectric thin films
77.22.Jp Dielectric breakdown and space-charge effects
85.30.Tv Field effect devices

Preparation of wide band gap microcrystalline silicon film by using SiH2Cl2

Sung Ki Kim, Byeong Yeon Moon, Jae Seong Byun, Hong Bin Jeon, and Jin Jang

Appl. Phys. Lett. 69, 1131 (1996); http://dx.doi.org/10.1063/1.117081 (3 pages) | Cited 6 times

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We have studied the growth of Cl incorporated microcrystalline silicon [μc‐Si(:Cl)]. The flow rates of H2 and SiH2Cl2 were varied to deposit wide band gap n+ μc‐Si(:Cl) films by using SiH4/SiH2Cl2/H2/PH3 mixtures. The n+ μc‐Si(:Cl) film deposited with SiH2Cl2/SiH4 = 1 exhibited a room temperature conductivity of 2 S/cm and an optical band gap of ∼2.0 eV that is at least 0.2 eV higher than that of conventional n+ μc‐Si. The surface morphology of the μc‐Si(:Cl) film is much rougher than that of conventional μc‐Si prepared by using SiH4/H2 plasma. © 1996 American Institute of Physics.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
72.80.Ng Disordered solids
73.61.Jc Amorphous semiconductors; glasses
68.55.-a Thin film structure and morphology

X‐ray reflectivity determination of interface roughness correlated with transport properties of (AlGa)As/GaAs high electron mobility transistor devices

J. A. Dura, J. G. Pellegrino, and C. A. Richter

Appl. Phys. Lett. 69, 1134 (1996); http://dx.doi.org/10.1063/1.117082 (3 pages) | Cited 6 times

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To explore the role of interface scattering in high electron mobility transistor (HEMT) device performance, a series of samples consisting of both a superlattice and a HEMT structure were grown by molecular beam epitaxy (MBE) at temperatures ranging from 500 to 630 °C. Hall measurements indicate a trend toward higher mobilities in samples grown at higher temperatures. Subsequent x‐ray reflectivity measurements were made, and the data were fitted by least‐squares refinement of a calculated reflectivity curve determined from a model of the sample structure to obtain the composition profile along the growth direction. These results indicate smoother interfaces for the samples with higher mobilities. © 1996 American Institute of Physics.
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61.05.cm X-ray reflectometry (surfaces, interfaces, films)
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.30.Tv Field effect devices

Polymeric light‐emitting diodes from molecularly thin poly(3‐hexylthiophene) Langmuir–Blodgett films

A. J. Pal, T. Östergård, J. Paloheimo, and H. Stubb

Appl. Phys. Lett. 69, 1137 (1996); http://dx.doi.org/10.1063/1.117083 (3 pages) | Cited 23 times

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Light‐emitting diodes based on molecularly thin films of a conjugated polymer have been fabricated. A few Langmuir–Blodgett layers of poly(3‐hexylthiophene) have been used as the active emitting material of the devices. Even the thinnest devices with only 3 monolayers, each having a thickness of ≊3 nm, yield the same luminance as thicker ones. The emission results from excitons in the polymer chains, and has a spectrum similar to that of photoluminescence, with a maximum at about 2.0 eV. © 1996 American Institute of Physics.
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85.65.+h Molecular electronic devices
85.60.Jb Light-emitting devices
68.18.-g Langmuir-Blodgett films on liquids
78.66.Qn Polymers; organic compounds

Effects of the oxidation process on the electrical characteristics of oxidized nitride films

M. K. Mazumder, T. Katayama, K. Kobayashi, Y. Mashiko, H. Koyama, and A. Yasuoka

Appl. Phys. Lett. 69, 1140 (1996); http://dx.doi.org/10.1063/1.117084 (3 pages) | Cited 1 time

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The effects of the oxidation process on the electrical characteristics of metal–oxide–semiconductor (MOS) capacitors were studied. It was found that electrical and time dependent dielectric breakdown (TDDB) characteristics are improved for the MOS capacitor with a wet oxidized nitride film over the N2O oxidized nitride film. The depth profile of the oxidized nitride film is also studied by Auger electron spectroscopy. It is observed that from the top surface of an oxidized nitride film of about 2 nm (nitride film oxidized in the wet oxidation process or in N2O ambient by rapid thermal processing), the level of oxygen is the same but, compared to a N2O oxidized nitride film, the level of nitrogen is greater in a wet oxidized nitride film. The improvement of the electrical and TDDB characteristics of the wet oxidized nitride film over the N2O oxidized nitride can be thought due to the increased amount of nitrogen from the top surface to a depth of nearly 2 nm of the oxidize nitride films. © 1996 American Institute of Physics.
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81.65.Mq Oxidation
85.30.Tv Field effect devices
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

CCl4‐doped semi‐insulating InP as a buffer layer in GaInAs/InP high electron mobility transistors

C. C. Hsu, Y. F. Yang, H. J. Ou, and E. S. Yang

Appl. Phys. Lett. 69, 1143 (1996); http://dx.doi.org/10.1063/1.117085 (2 pages) | Cited 3 times

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The application of CCl4‐doped semi‐insulating InP as a buffer layer in a pseudomorphic Ga0.2In0.8P/Ga0.47In0.53As/InP high electron mobility transistor (HEMT) grown by metalorganic chemical vapor deposition is reported. This Al‐free InP‐base HEMT with a gate length of 1.3 μm has extrinsic transconductances of 420 and 610 mS/mm at 300 and 77 K, respectively. A cutoff frequency of 15 GHz and a maximum oscillation frequency of 40 GHz are obtained. The results demonstrate the CCl4‐doped semi‐insulating InP is a promising buffer layer for InP‐based HEMT. © 1996 American Institute of Physics.
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85.30.Tv Field effect devices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Free versus localized exciton recombination in Zn1−xCdxSe/ZnSe multiple quantum wells

M. Lomascolo, M. Di Dio, D. Greco, L. Calcagnile, R. Cingolani, L. Vanzetti, L. Sorba, and A. Franciosi

Appl. Phys. Lett. 69, 1145 (1996); http://dx.doi.org/10.1063/1.117086 (3 pages) | Cited 6 times

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Time‐resolved photoluminescence studies of Zn1−xCdxSe/ZnSe multiple quantum wells as a function of photoinjected carrier density show a typical exciton localization dynamics at all injection levels in the high‐x samples (x∼0.2–0.3). On the contrary, the low‐x samples (x∼0.1) exhibit a gradual saturation of the exciton localization process and band‐filling behavior with increasing photoinjection. A rate‐equation model provides a description of the time‐dependent luminescence in all samples and allows a quantitative determination of the concentration of exciton localization centers. © 1996 American Institute of Physics.
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78.55.Et II-VI semiconductors
71.35.-y Excitons and related phenomena
78.47.-p Spectroscopy of solid state dynamics

Open boundary conditions for a time‐dependent analysis of the resonant tunneling structure

M. A. Talebian and W. Pötz

Appl. Phys. Lett. 69, 1148 (1996); http://dx.doi.org/10.1063/1.117087 (3 pages) | Cited 10 times

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Exact boundary conditions for open quantum devices with constant potential asymptotics are presented and implemented into a numerical treatment of the one‐dimensional time‐dependent Schrödinger equation. A time‐dependent analysis of the resonant tunneling double‐barrier (RTDB) structure demonstrates their superiority over previous approaches. Our self‐consistent study reveals microscopic details of the transient current in the system under an external time‐dependent bias. Two time regimes characterize the charge transport in a RTDB in response to an applied bias. The ultrafast response of the system occurs in the contact regions within approximately 100 fs. This response time is of the order of the inverse bulk plasma frequency and is essentially independent of the applied bias. The second time regime is characterized by current oscillations which sensitively depend on the applied bias and structural parameters. © 1996 American Institute of Physics.
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73.40.Gk Tunneling
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

Observation of Cu vacancies and their ordering in YBa2Cu4O8

N. D. Zakharov, G. Kästner, D. Hesse, and M. Lorenz

Appl. Phys. Lett. 69, 1151 (1996); http://dx.doi.org/10.1063/1.117088 (3 pages) | Cited 1 time

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Laser‐deposited epitaxial thin films of YBa2Cu3O7−δ investigated by high‐resolution transmission electron microscopy reveal narrow layers of the 1‐2‐4 phase YBa2Cu4O8. Within the CuO double layers of this phase, columns of double Cu(1) vacancies are identified to occur at periodic spacings of 2a with a, b, and c denoting the unit cell axes. In addition, an interchange of the a and b axes of the 1‐2‐4 phase is observed on traversing along c. A corresponding structure model is presented, and possible reasons of forming this structure by stress relaxation or by diffusional processes are discussed. A possible contribution to flux pinning is considered in the context of the supercurrent and high frequency properties. © 1996 American Institute of Physics.
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74.78.-w Superconducting films and low-dimensional structures
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)

Transport properties and giant magnetoresistance behavior in La‐Nd‐Sr‐Mn‐O films

Wei Zhang, Ian W. Boyd, Martin Elliott, and William Herrenden‐Harkerand

Appl. Phys. Lett. 69, 1154 (1996); http://dx.doi.org/10.1063/1.117089 (3 pages) | Cited 9 times

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The magnetoresistance of La‐Nd‐Sr‐Mn‐O films grown on Si(100) substrates using pulse laser deposition has been studied. Giant magnetoresistance behavior, with more than 70% (Δρ/ρ0) and 207% (Δρ/ρH) change in resistivity at 50 K under a magnetic field of 4.7 T has been obtained. The influence of the preparation conditions on the properties of the films grown is also described. © 1996 American Institute of Physics.
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75.47.De Giant magnetoresistance
73.61.Ng Insulators

A low‐noise single‐domain fluxgate sensor

J. Deak, A. H. Miklich, J. Slonczewski, and R. H. Koch

Appl. Phys. Lett. 69, 1157 (1996); http://dx.doi.org/10.1063/1.117090 (3 pages) | Cited 9 times

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In order to gain a better understanding of the noise mechanisms and limitations of fluxgate magnetometers, fluxgates with single and multidomain tubular permalloy cores were fabricated and tested. Under similar excitation conditions, single‐domain fluxgates show approximately two orders of magnitude better resolution than similarly sized multidomain fluxgates, indicating that domain wall motion is the mechanism that limits conventional multidomain fluxgate resolution. Noise in a single‐domain fluxgate was shown to decrease to 10−11 Trms/√Hz at 1 Hz as the drive and a superimposed circumferential magnetic field were increased. Results suggest that further noise reductions are possible. © 1996 American Institute of Physics.
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07.55.Ge Magnetometers for magnetic field measurements
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Nt Magnetic annealing and temperature-hysteresis effects

Enhancement of the magnetoresistance due to structural transition in Mg‐doped perovskite Mn oxides

A. Anane, C. Dupas, K. Le Dang, J. P. Renard, P. Veillet, L. Pinsard, and A. Revcolevschi

Appl. Phys. Lett. 69, 1160 (1996); http://dx.doi.org/10.1063/1.117381 (3 pages) | Cited 11 times

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Substitution of magnesium for manganese in mixed perovskite La1−xSrxMnO3was found to reduce the electrical conductivity and the Curie temperature Tc. A remarkable jump in the resistivity ρ was observed in the 6% Mg‐doped crystal with x=0.175. This sample remains semiconducting at low temperatures, contrary to the Mg‐free crystal. The abrupt change of ρ reflects a first‐order structural transition at a temperature Ts just below Tc. An applied magnetic field decreased Ts, leading to an enhancement of the magnetoresistance between Ts (0) and Ts (H). The microscopic properties of Mn3+ and Mn4+ ions due to Sr2+and Mg2+ substitutions were illustrated by 55Mn nuclear magnetic resonance study. © 1996 American Institute of Physics.
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75.47.De Giant magnetoresistance
75.50.Dd Nonmetallic ferromagnetic materials
61.50.Ks Crystallographic aspects of phase transformations; pressure effects

Study of CoCrPt/NiAl thin films on (001) MgO single crystals

L. Tang, L.‐L. Lee, D. E. Laughlin, and D. N. Lambeth

Appl. Phys. Lett. 69, 1163 (1996); http://dx.doi.org/10.1063/1.117382 (3 pages) | Cited 7 times

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The microstructure and in‐plane magnetic properties of Co72Cr10Pt18/NiAl thin films sputter deposited on (001) single crystal MgO substrates have been investigated. The orientation relationship between the NiAl underlayer and the MgO substrate is determined to be [001](100)NiAl//[001](110)MgO. The CoCrPt films grow in a fibrous manner on the (001) NiAl underlayer and the orientation relationship between the two layers is determined to be [1011]CoCrPt//[001]NiAl, and (1210)CoCrPt//(100)NiAl (variant 1), or (1210)CoCrPt//(010)NiAl (variant 2). The CoCrPt film has two sets of in‐plane magnetization easy axes. The major easy axes are along the MgO[100] (i.e., NiAl[110]) and the MgO[010] (i.e., NiAl[110]) directions and the secondary easy axes are along the MgO[110] (i.e., NiAl[100]) and the [110] (i.e., NiAl[010]) directions. © 1996 American Institute of Physics.
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75.70.Ak Magnetic properties of monolayers and thin films
68.55.-a Thin film structure and morphology
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)

Growth temperature dependence of long‐range alloy order and magnetic properties of epitaxial FexPt1−x (x≂0.5) films

R. F. C. Farrow, D. Weller, R. F. Marks, M. F. Toney, S. Hom, G. R. Harp, and A. Cebollada

Appl. Phys. Lett. 69, 1166 (1996); http://dx.doi.org/10.1063/1.117383 (3 pages) | Cited 87 times

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The structural and magnetic properties of 1000‐Å‐thick epitaxial FexPt1−x(001) alloy films, grown by molecular beam epitaxy with x≂0.5, have been studied as a function of growth temperature. X‐ray diffraction analysis showed that the long‐range order parameter increased from near zero for films grown at 100 °C to a maximum of 0.93 in films grown at 500 °C. Over this range the magnetic easy axis changed from in‐plane to perpendicular and the polar Kerr rotation increased strongly. Spontaneous long‐range ordering in these films has an activation energy ∼0.2 eV, consistent with an energy barrier for surface and step down diffusion. © 1996 American Institute of Physics.
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75.70.Ak Magnetic properties of monolayers and thin films
75.50.Bb Fe and its alloys
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Three‐dimensional image interaction for nonsmooth emitters

G. Mesa and J. J. Sáenz

Appl. Phys. Lett. 69, 1169 (1996); http://dx.doi.org/10.1063/1.118167 (3 pages) | Cited 9 times

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We present a generalized image–charge method to calculate the interaction energies of a charge placed between a metallic tip of arbitrary shape and a sample surface. The basic idea is to replace the electrodes by a set of image charges. These charges are adjusted in order to fit the boundary conditions on the surfaces. As an application of the technique, we have calculated the three‐dimensional potential barrier (including image interaction) for electron field emission from sharp tips having different geometries. The influence of the presence of a little hemispherical bump on the apex is also discussed. © 1996 American Institute of Physics.
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79.70.+q Field emission, ionization, evaporation, and desorption
41.20.Cv Electrostatics; Poisson and Laplace equations, boundary-value problems
07.79.-v Scanning probe microscopes and components
07.77.Ka Charged-particle beam sources and detectors
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