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4 Aug 2008

Volume 93, Issue 5, Articles (05xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 93, 051101 (2008); http://dx.doi.org/10.1063/1.2965797 (3 pages)

Mariano A. Zimmler, Jiming Bao, Federico Capasso, Sven Müller, and Carsten Ronning
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Local structure of indium oxynitride from x-ray absorption spectroscopy

J. T-Thienprasert, J. Nukeaw, A. Sungthong, S. Porntheeraphat, S. Singkarat, D. Onkaw, S. Rujirawat, and S. Limpijumnong

Appl. Phys. Lett. 93, 051903 (2008); http://dx.doi.org/10.1063/1.2965802 (3 pages) | Cited 8 times

Online Publication Date: 5 August 2008

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Synchrotron x-ray absorption near edge structures (XANES) measurements of In L3 edge is used in conjunction with first principles calculations to characterize rf magnetron sputtered indium oxynitride at different O contents. Good agreement between the measured and the independently calculated spectra are obtained. Calculations show that the XANES spectra of this alloy are sensitive to the coordination numbers of the In atoms, i.e., fourfold for indium nitride-like structures and sixfold for indium oxide-like structures, but not to the substitution of nearest neighbor N by O or vice versa.
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78.70.Dm X-ray absorption spectra
61.66.Fn Inorganic compounds
81.15.Cd Deposition by sputtering

Resonant Raman scattering from polyacetylene and poly(p-phenylene vinylene) chains included into hydrogenated amorphous carbon

M. Rybachuk, A. Hu, and J. M. Bell

Appl. Phys. Lett. 93, 051904 (2008); http://dx.doi.org/10.1063/1.2965458 (3 pages) | Cited 5 times

Online Publication Date: 5 August 2008

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The resonant Raman scattering in N-IR–UV range from amorphous hydrogenated carbon (a-C:H) reveals inclusions of trans-polyacetylene [trans-(CH)x] chains with approximate length of up to 120 C=C units and inclusions of poly(p-phenylene vinylene) (PPV) polymer chains. The PPV is evidenced by a strong dispersive mode at ∼ 1175 cm−1. It was found that the Raman response from core Ag trans-(CH)x modes incorporated into a−C:H to changing excitation energy is identical to that of freestanding chains, thus facilitating identification of trans-(CH)x in complex carbonaceous materials spectra.
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78.35.+c Brillouin and Rayleigh scattering; other light scattering
78.40.Pg Disordered solids
61.43.Er Other amorphous solids

Sharp growth of nickel plasticity under impact load near Curie point

Michel Molotskii

Appl. Phys. Lett. 93, 051905 (2008); http://dx.doi.org/10.1063/1.2965489 (3 pages) | Cited 3 times

Online Publication Date: 5 August 2008

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We proposed an explanation of the recent observations by Zaretsky [Appl. Phys. Lett. 92, 011913 (2008)] who discovered sharp increase in nickel plasticity under impact loading near Curie temperature TC. Growth of plasticity is explained by reduction in dynamical deceleration of dislocations controlled by their interaction with paramagnetic obstacles. The decreased contribution of these obstacles is due to spin-dependent transitions in internal magnetic field of ferromagnetic in radical pair dislocation-obstacle from strong to weak bonding states. The main contribution to the effect is from fields of magnetic fluctuations which have a large growth near Curie point.
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62.20.fq Plasticity and superplasticity
75.30.Cr Saturation moments and magnetic susceptibilities
61.72.Bb Theories and models of crystal defects
75.20.En Metals and alloys
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
81.40.Lm Deformation, plasticity, and creep

Morphology and flexibility of graphene and few-layer graphene on various substrates

U. Stöberl, U. Wurstbauer, W. Wegscheider, D. Weiss, and J. Eroms

Appl. Phys. Lett. 93, 051906 (2008); http://dx.doi.org/10.1063/1.2968310 (3 pages) | Cited 42 times

Online Publication Date: 6 August 2008

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We report on detailed microscopy studies of graphene and few-layer graphene produced by mechanical exfoliation on various semiconducting substrates. We demonstrate the possibility to prepare and analyze graphene on (001)-GaAs, manganese p-doped (001)-GaAs, and InGaAs substrates. The morphology of graphene on these substrates was investigated by scanning electron and atomic force microscopies and compared to layers on SiO2. It was found that graphene sheets strongly follow the texture of the sustaining substrates independent on doping, polarity, or roughness. Furthermore resist residues exist on top of graphene after a lithographic step. The obtained results provide the opportunity to research the graphene-substrate interactions.
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61.46.-w Structure of nanoscale materials
68.47.Fg Semiconductor surfaces
68.35.bt Other materials
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Ps Atomic force microscopy (AFM)

Effect of grain orientation on ductility in a nanocrystalline Ni–Fe alloy

Hongqi LI, Peter K. Liaw, Hahn Choo, and Amit Misra

Appl. Phys. Lett. 93, 051907 (2008); http://dx.doi.org/10.1063/1.2968662 (3 pages) | Cited 5 times

Online Publication Date: 6 August 2008

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The influence of columnar grain geometry on mechanical property was studied in an electrodeposited nanocrystalline Ni–Fe alloy. The compressive results show that the strength is independent of grain orientation. However, the plastic strain increased remarkably when the loading axis is parallel to the direction of grain columns, which is due to the enhanced grain boundary and dislocation activities. The significance of the current study is that a new strategy was developed to improve the ductility of nanocrystalline materials.
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61.72.Mm Grain and twin boundaries
81.40.Lm Deformation, plasticity, and creep
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Electromigration-driven motion of an elliptical inclusion

Z. Li and N. Chen

Appl. Phys. Lett. 93, 051908 (2008); http://dx.doi.org/10.1063/1.2968718 (3 pages) | Cited 3 times

Online Publication Date: 6 August 2008

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We present a rigorous analytical solution for electromigration-driven motion of an elliptical inclusion in an infinite two-dimensional conductor (here, an inclusion may imply a void). An elliptical inclusion will move at a velocity proportional to the applied electric field strength, inversely proportional to an equivalent inclusion size, and strongly affected by the shape parameter of the inclusion, but independent of rotation of the inclusion with respect to the direction of the applied electric field. For a given equivalent inclusion size, a circular inclusion will move at the lowest velocity, while a slitlike one moves quickly.
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85.40.Ls Metallization, contacts, interconnects; device isolation

Room temperature epitaxial stabilization of a tetragonal phase in ARuO3 (A = Ca and Sr) thin films

Arturas Vailionis, Wolter Siemons, and Gertjan Koster

Appl. Phys. Lett. 93, 051909 (2008); http://dx.doi.org/10.1063/1.2967878 (3 pages) | Cited 19 times

Online Publication Date: 6 August 2008

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We demonstrate that SrRuO3 and CaRuO3 thin films undergo a room temperature structural phase transition driven by the substrate imposed epitaxial biaxial strain. As tensile strain increases, ARuO3 (A = Ca and Sr) films transform from the orthorhombic phase which is usually observed in bulk SrRuO3 and CaRuO3 at room temperature into a tetragonal phase which in bulk samples is only stable at higher temperatures. More importantly, we show that the observed phenomenon strongly affects the electronic and magnetic properties of ARuO3 thin films that are grown on different single crystal substrates which, in turn, offers the possibility to tune these properties.
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68.55.-a Thin film structure and morphology
64.70.K- Solid-solid transitions
68.60.Bs Mechanical and acoustical properties
71.20.Ps Other inorganic compounds
75.70.Ak Magnetic properties of monolayers and thin films

Indicators of internal structural states for metallic glasses: Local order, free volume, and configurational potential energy

Y. Q. Cheng and E. Ma

Appl. Phys. Lett. 93, 051910 (2008); http://dx.doi.org/10.1063/1.2966154 (3 pages) | Cited 6 times

Online Publication Date: 7 August 2008

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The structural states of metallic glasses (MGs) have been described previously using concepts such as free volume and configurational potential energy. Here we discuss the inadequacy of these indicators by examining a Cu–Zr–Al MG model experiencing different cooling and relaxation history. The results identify the local (icosahedral) ordering as a fundamental process underlying structural relaxation, and the degree of order as a more sensitive and revealing structural indicator.
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61.43.Fs Glasses

Photoconductivity in defective carbon nanotube sheets under ultraviolet–visible–near infrared radiation

M. Passacantando, F. Bussolotti, V. Grossi, S. Santucci, A. Ambrosio, M. Ambrosio, G. Ambrosone, V. Carillo, U. Coscia, P. Maddalena, E. Perillo, and A. Raulo

Appl. Phys. Lett. 93, 051911 (2008); http://dx.doi.org/10.1063/1.2968203 (3 pages) | Cited 11 times

Online Publication Date: 8 August 2008

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Multiwalled carbon nanotube sheets of relatively large area have been grown on a sapphire substrate by chemical vapor deposition at the substrate temperature of 500 and 750 °C. The photoconductivity measurements, performed under white light and monochromatic radiation in the ultraviolet–visible–near infrared region, show that the highly defective sample grown at 500 °C has a higher photosensitivity, thus revealing the crucial role of structural defects in determining the overall photoresponse of the nanotube’s sheets. The spectral photoresponse of these nanostructured films increases with the increase in photon energy, and is strongly correlated to the absorbance. The photoconductivity properties of these materials are favorable in potential development of large area light sensors as well as optoelectronic nanodevices.
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73.63.Fg Nanotubes
73.61.Cw Elemental semiconductors
73.50.Pz Photoconduction and photovoltaic effects
61.48.De Structure of carbon nanotubes, boron nanotubes, and other related systems
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
72.40.+w Photoconduction and photovoltaic effects

Stokes and anti-Stokes resonant Raman scatterings from biased GaN/AlN heterostructure

Guibao Xu, Suvranta K. Tripathy, Xiaodong Mu, Yujie J. Ding, Kejia Wang, Yu Cao, Debdeep Jena, and Jacob B. Khurgin

Appl. Phys. Lett. 93, 051912 (2008); http://dx.doi.org/10.1063/1.2967337 (3 pages) | Cited 8 times

Online Publication Date: 8 August 2008

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An electric field present in a GaN/AlN heterostructure can bring both the first-order and second-order Raman scattering processes into strong resonances. The resonant Stokes and anti-Stokes Raman scatterings result in the increase and decrease in nonequilibrium longitudinal-optical phonon temperatures, respectively. Moreover, the phonon temperature measured from the Raman scattering is increased with an applied electric field at a much higher rate than the lattice temperature due to the presence of field-induced nonequilibrium longitudinal-optical phonons.
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78.30.Fs III-V and II-VI semiconductors
63.20.-e Phonons in crystal lattices

Optical polarization properties of interband transitions in strained group-III-nitride alloy films on GaN substrates with nonpolar orientation

Jayeeta Bhattacharyya, Sandip Ghosh, and H. T. Grahn

Appl. Phys. Lett. 93, 051913 (2008); http://dx.doi.org/10.1063/1.2965119 (3 pages) | Cited 25 times

Online Publication Date: 8 August 2008

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The authors present results of a perturbation theory study of the combined effects of composition and anisotropic in-plane strain on the optical polarization properties of the three interband transitions in the vicinity of the fundamental energy gap of wurtzite group-III-nitride alloy films, pseudomorphically grown on GaN substrates with nonpolar orientation such as M-plane GaN(1math00). Valence band mixing induced by the anisotropic in-plane strain is shown to have a dramatic influence on the optical polarization properties. The results indicate that an increased efficiency of light emission in the visible spectral range can be achieved with compressively strained InxGa1−xN active layers. While AlxGa1−xN layers under tensile strain will exhibit a very poor light emission efficiency in the ultraviolet (UV) spectral range, efficient emission in the UV range can instead be achieved with InxAl1−xN films. These results also hold for alloy films on A-plane GaN(11math0) substrates.
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78.66.Fd III-V semiconductors
71.20.-b Electron density of states and band structure of crystalline solids
78.40.Fy Semiconductors
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Investigation of two-branch boron diffusion from vapor phase in n-type 4H-SiC

A. V. Bolotnikov, P. G. Muzykov, and T. S. Sudarshan

Appl. Phys. Lett. 93, 052101 (2008); http://dx.doi.org/10.1063/1.2968306 (3 pages) | Cited 5 times

Online Publication Date: 6 August 2008

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Boron diffusion from gas phase was implemented for p-type doping of 4H-SiC at temperatures in the range of 1800–2000 °C. A two-branch diffusion associated with two different diffusion mechanisms was observed. The activation energy Ea and prefactor D0 were calculated for each diffusion branch, that are Ea = 7.258 eV/D0 = 1.931×106 cm2/s and Ea = 8.742 eV/D0 = 2.126×107 cm2/s for fast and slow diffusion, respectively. It has been confirmed that the surface layer of diffused boron mostly consists of shallow boron acceptors, while the tail of diffusion profile has mostly deep level D centers.
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66.30.J- Diffusion of impurities
71.55.Ht Other nonmetals

Suppression of annealing-induced In diffusion in Be-doped GaInAsN/GaAs quantum well

J. Pakarinen, C. S. Peng, V. Polojärvi, A. Tukiainen, V.-M. Korpijärvi, J. Puustinen, M. Pessa, P. Laukkanen, J. Likonen, and E. Arola

Appl. Phys. Lett. 93, 052102 (2008); http://dx.doi.org/10.1063/1.2966146 (3 pages) | Cited 7 times

Online Publication Date: 6 August 2008

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The authors report on an interesting observation regarding thermal annealing of a beryllium-doped Ga0.65In0.35As0.99N0.01/GaAs quantum well (QW) grown by molecular beam epitaxy. A QW doped at 6×1019 cm−3 exhibited superior thermal properties and about six times larger photoluminescence than an undoped QW of the same structure. X-ray diffraction and secondary ion mass spectrometry provided evidence that beryllium suppressed indium diffusion and stabilized (metastable) dilute nitride heterostructure upon annealing.
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66.30.Pa Diffusion in nanoscale solids
68.65.Fg Quantum wells
61.72.uj III-V and II-VI semiconductors
78.55.Cr III-V semiconductors
81.40.Gh Other heat and thermomechanical treatments

Intraband Auger effect in InAs/InGaAlAs/InP quantum dot structures

T. Gebhard, D. Alvarenga, P. L. Souza, P. S. S. Guimarães, K. Unterrainer, M. P. Pires, G. S. Vieira, and J. M. Villas-Boas

Appl. Phys. Lett. 93, 052103 (2008); http://dx.doi.org/10.1063/1.2965804 (3 pages) | Cited 3 times

Online Publication Date: 7 August 2008

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InAs quantum dot structures grown on InGaAlAs have been investigated for midinfrared photodetection. Intraband photocurrent and absorption measurements, together with a full three-dimensional theoretical modeling revealed that a bound-to-bound optical transition, where the final state is about 200 meV deep below the conduction band continuum, is responsible for the photogenerated current. The reported results strongly suggest that an Auger process plays a fundamental role in generating the observed intraband photocurrent. Photoluminescence and interband photocurrent spectra of the same structures further support the reached conclusions.
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73.21.La Quantum dots
78.67.Hc Quantum dots
68.65.Hb Quantum dots (patterned in quantum wells)
72.40.+w Photoconduction and photovoltaic effects
79.20.Fv Electron impact: Auger emission
79.60.Bm Clean metal, semiconductor, and insulator surfaces
78.55.Cr III-V semiconductors

Band alignment and thermal stability of HfO2 gate dielectric on SiC

Q. Chen, Y. P. Feng, J. W. Chai, Z. Zhang, J. S. Pan, and S. J. Wang

Appl. Phys. Lett. 93, 052104 (2008); http://dx.doi.org/10.1063/1.2969061 (3 pages) | Cited 10 times

Online Publication Date: 7 August 2008

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The band alignment and thermal stability for HfO2 films on SiC with and without nitridation have been studied by using photoemission spectroscopy. The valence- and conduction-band offsets at HfO2/4H-SiC interfaces were measured to be 1.02 and 1.53 eV, respectively. The atomic source nitridation improves interface thermal stability with nitrogen passivation for the oxygen vacancies in dielectric films and for the defects on SiC surface, but induces band gap reduction for the HfO2 dielectric layer and band alignment shift at the interface. Postnitridation annealing helps to improve the band offsets of dielectric film to have sufficient injection barrier.
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73.20.At Surface states, band structure, electron density of states
77.55.-g Dielectric thin films
79.60.Jv Interfaces; heterostructures; nanostructures
61.72.jd Vacancies

Electron mobility in phosphorous doped {111} homoepitaxial diamond

J. Pernot and S. Koizumi

Appl. Phys. Lett. 93, 052105 (2008); http://dx.doi.org/10.1063/1.2969066 (3 pages) | Cited 8 times

Online Publication Date: 7 August 2008

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The room temperature Hall electron mobility of phosphorous doped {111} homoepitaxial diamond is investigated experimentally and described theoretically for different doping and compensating center densities. The impurities mobility dependence is established. The mobility is found to be controlled by the lattice scattering mechanisms in low doped material (below 1017 cm−3), by lattice and ionized impurity scattering for moderate doping level (1017 cm−3<ND<1018 cm−3), and by neutral impurity scattering for highly doped material (above 1018 cm−3). The mobility parameters required to simulate the electric characteristics of electronic devices between 300 and 500 K in a wide doping range are then determined.
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73.61.Cw Elemental semiconductors
72.10.Fk Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect)
61.72.sd Impurity concentration
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Metal nanocrystals synthesized with a micellar template based on a diblock copolymer for three-dimensional nonvolatile memory

Chung-Jin Kim, Seong-Wan Ryu, Yang-Kyu Choi, Jae-Joon Chang, Su Hak Bae, and Byeong-Hyeok Sohn

Appl. Phys. Lett. 93, 052106 (2008); http://dx.doi.org/10.1063/1.2969051 (3 pages) | Cited 8 times

Online Publication Date: 8 August 2008

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Metal nanocrystals synthesized with a micellar template were applied for three-dimensional vertical floating gate memory devices. Using a highly ordered micellar template formed with a diblock copolymer, we produced cobalt (Co) nanocrystals with a uniform size and spatial distribution on a planar surface and a sidewall surface. The hydrogen annealing effects were investigated in terms of memory performance. The fabricated vertical floating gate memory with Co nanocrystals annealed with hydrogen showed a memory window with a voltage greater than 1 V and a retention time characteristic that preserves more than 60% of the initial charge after ten years.
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84.30.Sk Pulse and digital circuits
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Quasiparticle cooling of a single Cooper pair transistor

A. J. Ferguson

Appl. Phys. Lett. 93, 052501 (2008); http://dx.doi.org/10.1063/1.2968214 (3 pages) | Cited 2 times

Online Publication Date: 5 August 2008

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A superconducting tunnel junction is used to directly extract quasiparticles from one of the leads of a single Cooper pair transistor. The consequent reduction in quasiparticle density causes a lower rate of quasiparticle tunneling onto the device. This rate is directly measured by radio-frequency reflectometry. Local cooling may be of direct benefit in reducing the effect of quasiparticles on coherent superconducting nanostructures.
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85.25.Cp Josephson devices
85.25.Am Superconducting device characterization, design, and modeling

Magnetic anisotropy in ferromagnetic Josephson junctions

M. Weides

Appl. Phys. Lett. 93, 052502 (2008); http://dx.doi.org/10.1063/1.2967873 (3 pages) | Cited 10 times

Online Publication Date: 5 August 2008

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Magnetotransport measurements were done on Nb/Al2O3/Cu/Ni/Nb superconductor-insulator-ferromagnet-superconductor Josephson tunnel junctions. Depending on ferromagnetic Ni interlayer thickness and geometry, the standard (1d) magnetic field dependence of critical current deviates from the textbook model for Josephson junctions. The results are qualitatively explained by a short Josephson junction model based on anisotropy and 2d remanent magnetization.
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74.25.Ha Magnetic properties including vortex structures and related phenomena
74.25.F- Transport properties
74.50.+r Tunneling phenomena; Josephson effects
74.25.Sv Critical currents
74.70.Ad Metals; alloys and binary compounds (including A15, MgB2, etc.)

Underlying mechanism of domain-wall motions in soft magnetic thin-film nanostripes beyond the velocity-breakdown regime

Sang-Koog Kim, Jun-Young Lee, Youn-Seok Choi, Konstantin Yu. Guslienko, and Ki-Suk Lee

Appl. Phys. Lett. 93, 052503 (2008); http://dx.doi.org/10.1063/1.2968138 (3 pages) | Cited 16 times

Online Publication Date: 6 August 2008

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It is known that oscillatory domain-wall (DW) motions in soft magnetic thin-film nanostripes above the Walker critical field lead to remarkable reductions in the average DW velocities. In a much-higher-field region beyond the velocity-breakdown regime, however, the DW velocities have been found to increase in response to a further increase of the applied field. We report on the physical underlying mechanism of this unexpected behavior. We associate the mechanism with the serial dynamic processes of the nucleation of vortex-antivortex pairs inside the stripe or at its edges, the nonlinear gyrotropic motions of vortices and antivortices, and their annihilation process. Moreover, this work evidences that a two-dimensional soliton model is required for adequate interpretation and understanding of DW motions in the linear- and oscillatory-DW-motion regimes as well as in the beyond-velocity-breakdown regime.
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75.75.-c Magnetic properties of nanostructures
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Ch Domain walls and domain structure
75.40.Mg Numerical simulation studies
75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
75.70.Ak Magnetic properties of monolayers and thin films

Element- and site-specific oxidation state and cation distribution in manganese ferrite films by diffraction anomalous fine structure

Aria Yang, Zhaohui Chen, Anton L. Geiler, Xu Zuo, Daniel Haskel, E. Kravtsov, C. Vittoria, and V. G. Harris

Appl. Phys. Lett. 93, 052504 (2008); http://dx.doi.org/10.1063/1.2969406 (3 pages) | Cited 4 times

Online Publication Date: 8 August 2008

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Epitaxial manganese ferrite thin films were studied by x-ray diffraction anomalous fine structure to obtain element-specific and site-specific information on site occupancy, local structure, and valency. These properties were introduced to molecular field theory to reproduce thermomagnetization curves and determine superexchange energy, Néel temperature, and spin canting angle.
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68.55.-a Thin film structure and morphology
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

Coercivity mechanism of hydrogenation disproportionation desorption recombination processed Nd–Fe–B based magnets

W. F. Li, T. Ohkubo, K. Hono, T. Nishiuchi, and S. Hirosawa

Appl. Phys. Lett. 93, 052505 (2008); http://dx.doi.org/10.1063/1.2969416 (3 pages) | Cited 13 times

Online Publication Date: 8 August 2008

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We have investigated the microstructure change of hydrogenation disproportionation desorption recombination processed Nd12.5Fe73Co8B6.5 powders during the desorption recombination (DR) stage to understand the mechanism of the coercivity development in the DR process. A uniform Nd-enriched layer was found to form along the grain boundaries when coercivity starts to increase in the DR process, which should be the main reason for the coercivity development. However, the composition of this grain boundary layer was found to contain a high concentration of ferromagnetic elements.
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75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
82.30.-b Specific chemical reactions; reaction mechanisms
75.50.Tt Fine-particle systems; nanocrystalline materials
68.43.Nr Desorption kinetics
75.50.Bb Fe and its alloys
61.72.Mm Grain and twin boundaries
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Ferroelectric, electrical and magnetic properties of Cr, Mn, Co, Ni, Cu added polycrystalline BiFeO3 films

Hiroshi Naganuma, Jun Miura, and Soichiro Okamura

Appl. Phys. Lett. 93, 052901 (2008); http://dx.doi.org/10.1063/1.2965799 (3 pages) | Cited 49 times

Online Publication Date: 4 August 2008

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Cr, Mn, Co, Ni, and Cu were added to polycrystalline BiFeO3 films, and their influence on the ferroelectric, electrical, and magnetic properties was investigated. All the additives except Ni reduced the leakage current density in the high electric field region. The addition of Cu and Co decreased the coercive field without reducing remanent polarization. The addition of Co caused spontaneous magnetization at room temperature, which exhibited a large coercive field of 16 kOe at 10 K. It was revealed that Co addition suppressed the leakage current density, decreased the electric coercive field, and induced spontaneous magnetization and large magnetic coercivity.
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75.80.+q Magnetomechanical effects, magnetostriction
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.-g Dielectric thin films
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
73.61.Ng Insulators

SmScO3 thin films as an alternative gate dielectric

E. Durğun Özben, J. M. J. Lopes, M. Roeckerath, St. Lenk, B. Holländer, Y. Jia, D. G. Schlom, J. Schubert, and S. Mantl

Appl. Phys. Lett. 93, 052902 (2008); http://dx.doi.org/10.1063/1.2968660 (3 pages) | Cited 12 times

Online Publication Date: 5 August 2008

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Samarium scandate thin films deposited on (100) Si have been investigated structurally and electrically. Rutherford backscattering spectrometry and transmission electron microscopy results show that the films are stoichiometric, amorphous, and smooth. X-ray diffraction analysis indicates that SmScO3 starts to crystallize at 900 °C. Capacitance and leakage current measurements reveal C-V curves with negligible hysteresis, a dielectric constant around 29 for 6 nm thick films, low leakage current densities in the range of 10−7 A/cm2, an effective oxide charge density of ∼ 5×1011 cm−2, and an interface trap density of 4.5×1011 (eV cm2)−1.
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77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
61.43.Er Other amorphous solids
77.80.Dj Domain structure; hysteresis
77.22.Ch Permittivity (dielectric function)

Low temperature improvement on silicon oxide grown by electron-gun evaporation for resistance memory applications

Chih-Tsung Tsai, Ting-Chang Chang, Po-Tsun Liu, Yi-Li Cheng, and Fon-Shan Huang

Appl. Phys. Lett. 93, 052903 (2008); http://dx.doi.org/10.1063/1.2957655 (3 pages) | Cited 3 times

Online Publication Date: 5 August 2008

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In this work, the supercritical CO2 fluid mixed with cosolvents is introduced to terminate the traps in electron-gun (e-gun) evaporation deposited silicon oxide (SiOx) film at 150 °C. After the proposed treatment, the SiOx film exhibits a lower leakage current and a resistive switching behavior that is controllable by applying proper voltage bias. The change in resistance is over 102 times and the retention time attains to 2×103 s. It is also discovered that the resistive switching behavior seemingly relates to the amount of traps.
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81.05.-t Specific materials: fabrication, treatment, testing, and analysis
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.aj Insulators
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