APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

16 Mar 2009

Volume 94, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 111101 (2009); http://dx.doi.org/10.1063/1.3097278 (3 pages)

Ling Lu, Adam Mock, Tian Yang, Min Hsiung Shih, Eui Hyun Hwang, Mahmood Bagheri, Andrew Stapleton, Stephen Farrell, John O’Brien, and P. Daniel Dapkus
Enlarge Image | Read More
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Semiconductor point defect concentration profiles measured using coherent acoustic phonon waves

A. Steigerwald, Y. Xu, J. Qi, J. Gregory, X. Liu, J. K. Furdyna, K. Varga, A. B. Hmelo, G. Lüpke, L. C. Feldman, and N. Tolk

Appl. Phys. Lett. 94, 111910 (2009); http://dx.doi.org/10.1063/1.3099341 (3 pages) | Cited 5 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Coherent acoustic phonon interferometry is used to quantitatively measure depth-dependent point defect concentrations in semiconductor systems with a depth range of the order of tens of microns. Using time-resolved pump-probe techniques, the optical response of ion-beam irradiated GaAs crystals is analyzed as a function of defect concentration ranging over four orders of magnitude. Varying the ion dose quantitatively relates changes in the optical response to local defect concentrations. Thermal annealing is shown to reduce the effect on the optical response, indicating recovery of the crystal lattice through self-interstitial-vacancy recombination.
Show PACS
61.72.jd Vacancies
61.72.jj Interstitials
61.80.Jh Ion radiation effects
61.72.Cc Kinetics of defect formation and annealing
78.47.D- Time resolved spectroscopy (>1 psec)
62.65.+k Acoustical properties of solids

Conformational characteristics of β-glucan in laminarin probed by terahertz spectroscopy

Hee Jun Shin, Seung Jae Oh, Sung In Kim, Ha Won Kim, and Joo-Hiuk Son

Appl. Phys. Lett. 94, 111911 (2009); http://dx.doi.org/10.1063/1.3100778 (3 pages) | Cited 1 time

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We measured the binding-state-dependent power absorptions, refractive indices, and dielectric constants of triple-stranded helices (TSHs) and single-stranded helices (SSHs) β-glucans in laminarin using terahertz time-domain spectroscopy (TDS). The SSH β-glucan was obtained from a TSH β-glucan laminarin by a chemical treatment with NaOH solution. The power absorption of TSH β-glucan increased more rapidly than that of the SSH β-glucan with the frequency increment. The refractive index and dielectric constants of TSH β-glucan were also larger than those of the SSH β-glucan. This result implies that terahertz-TDS is a very effective method in classifying the conformational state of β-glucans.
Show PACS
87.64.K- Spectroscopy
87.15.Pc Electronic and electrical properties
87.15.hp Conformational changes
87.14.Df Carbohydrates
87.15.Fh Bonding; mechanisms of bond breakage

Multilayered optical bit memory with a high signal-to-noise ratio in fluorescent polymethylmethacrylate

Zhaogang Nie, Heungyeol Lee, Hyeonggeun Yoo, Youlee Lee, Younshil Kim, Ki-Soo Lim, and Myeongkyu Lee

Appl. Phys. Lett. 94, 111912 (2009); http://dx.doi.org/10.1063/1.3103365 (3 pages) | Cited 9 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the three-dimensional optical memory utilizing a photoluminescence (PL) change in polymethylmethacrylate. Irradiation with a femtosecond pulsed laser (800 nm, 1 kHz, 100 fs) induced a strong PL spectrum in the visible range, which may result from the photogeneration of emissive radicals. Multilayered patterns were recorded inside the bulk sample by tightly focusing a pulsed laser beam. The pattern images were read out by a reflection-type fluorescent confocal microscope which detected the blue-green emission at 410–510 nm. The stored bits were retrieved with a high signal-to-noise ratio in the absence of any cross-talk.
Show PACS
42.79.Vb Optical storage systems, optical disks
78.55.Hx Other solid inorganic materials
78.55.Kz Solid organic materials
42.70.-a Optical materials
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Control performance of a single-chip white light emitting diode by adjusting strain in InGaN underlying layer

X. H. Wang, L. W. Guo, H. Q. Jia, Z. G. Xing, Y. Wang, X. J. Pei, J. M. Zhou, and H. Chen

Appl. Phys. Lett. 94, 111913 (2009); http://dx.doi.org/10.1063/1.3103559 (3 pages) | Cited 5 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Light emission from green to white in a single-chip light emitting diode is modulated by adjusting the strain in InGaN underlying layer (UL) embedded below an active layer of InGaN/GaN multiple quantum wells. Transmission electron microscopy combined with x-ray reciprocal space mapping reveals that indium phase separation in InGaN quantum well active layer is enhanced by using a partly relaxed InGaN UL and In-rich quantum dots with different size and indium composition are formed. They emit multicolor lights whose mixing produces white light. Quality of the white light could be controlled by modulation on relaxation degree of the InGaN UL.
Show PACS
85.60.Jb Light-emitting devices
85.60.Bt Optoelectronic device characterization, design, and modeling
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Valence-differential spectroscopy of Co–Fe cyanide films

Y. Moritomo, F. Nakada, and Y. Kurihara

Appl. Phys. Lett. 94, 111914 (2009); http://dx.doi.org/10.1063/1.3103561 (3 pages) | Cited 3 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electrochromism is extensively investigated for practical application of display and memory devices. To develop the material, reliable information on the optical and electronic properties of the solid film is indispensable. Here, we propose valence-differential spectroscopy that can selectively extract the spectral components related to the oxidized/reduced metal site. We applied the spectroscopy to Co2+–Fe2+δ and Co2+δ–Fe2+ cyanide films with finely control of averaged valence (δ) of the transition metal by external electric pulses. The spectroscopy revealed transition energy E, width Γ, and oscillator strength f of the spectral components related to the transition metal.
Show PACS
78.66.-w Optical properties of specific thin films
78.20.Jq Electro-optical effects

Electric field controlled formation and dissociation of multiwalled carbon nanotube conductive pathways in a polymer melt

Cheng Zhang, Jun Zhu, Mi Ouyang, and Chun-an Ma

Appl. Phys. Lett. 94, 111915 (2009); http://dx.doi.org/10.1063/1.3103549 (3 pages) | Cited 10 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electric field controlled formation and dissociation of multiwalled carbon nanotube (MWCNT) conductive pathways in a polycarbonate (PC) melt are investigated by the dynamic percolation measurement. The results show that field-induced MWCNT alignment causes the decrease in the activation energy of conductive pathway formation. The directional or disordered alignment of MWCNTs in the PC melt results in the transition from a conductor to an insulator as the electric field changes from 500 to 1 V/cm. This electric-controllable directional or disordered alignment technology is promising for the fabrication of low-dimensional conductive materials and applications of voltage-switch devices.
Show PACS
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
72.80.Tm Composite materials
61.48.De Structure of carbon nanotubes, boron nanotubes, and other related systems
back to top
RSS Feeds

Carrier transport mechanisms of nonvolatile write-once-read-many-times memory devices with InP–ZnS core-shell nanoparticles embedded in a polymethyl methacrylate layer

Jung Hoon Ham, Do Hyun Oh, Sung Hwan Cho, Jae Hun Jung, Tae Whan Kim, Eui Dock Ryu, and Sang Wook Kim

Appl. Phys. Lett. 94, 112101 (2009); http://dx.doi.org/10.1063/1.3097805 (3 pages) | Cited 9 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Current-voltage (I-V) curves at 300 K for Al/InP–ZnS nanoparticles embedded in a polymethyl methacrylate layer/Al devices showed electrical bistability for write-once-read-many-times (WORM) memory devices. From the I-V curves, the ON/OFF ratio for the device with InP–ZnS nanoparticles was significantly larger than that for the device without InP–ZnS nanoparticles, indicative of the existence of charge capture in the InP nanoparticles. The estimated retention time of the ON state for the WORM memory device was more than 10 years. The carrier transport mechanisms for the WORM memory devices are described by using several models to fit the experimental I-V data.
Show PACS
84.30.Sk Pulse and digital circuits
81.07.Bc Nanocrystalline materials

Dislocation core effect scattering in a quasitriangle potential well

Xiaoqing Xu, Xianglin Liu, Shaoyan Yang, Jianming Liu, Hongyuan Wei, Qinsheng Zhu, and Zhanguo Wang

Appl. Phys. Lett. 94, 112102 (2009); http://dx.doi.org/10.1063/1.3098356 (3 pages) | Cited 5 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A theory of scattering by charged dislocation lines in a quasitriangle potential well of AlxGa1−xN/GaN heterostructures is developed. The dependence of mobility on carrier sheet density and dislocation density is obtained. The results are compared with those obtained from a perfect two-dimensional electron gas and the reason for discrepancy is given.
Show PACS
61.72.Bb Theories and models of crystal defects
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.20.Dp General theory, scattering mechanisms
72.20.Ee Mobility edges; hopping transport

Cathodoluminescence study of dislocation-related luminescence from small-angle grain boundaries in multicrystalline silicon

Woong Lee, Jun Chen, Bin Chen, Jiho Chang, and Takashi Sekiguchi

Appl. Phys. Lett. 94, 112103 (2009); http://dx.doi.org/10.1063/1.3099001 (3 pages)

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dislocation-related luminescence from small-angle grain boundaries (SA-GBs) in multicrystalline Si was investigated by cathodoluminescence. D3 and D4 emissions were detected at SA-GBs with a misorientation angle of around 1°–1.5°, and D1 and D2 at SA-GBs with a misorientation angle of around 2°–2.5°. Electron beam-induced current investigations indicate that the former SA-GBs possess only shallow energy levels, while the latter possess both deep and shallow levels. The origins of D-line luminescence at SA-GBs are discussed in terms of dislocation structures.
Show PACS
78.60.Hk Cathodoluminescence, ionoluminescence
61.72.Mm Grain and twin boundaries
78.55.Ap Elemental semiconductors
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
71.55.Cn Elemental semiconductors
72.80.Cw Elemental semiconductors

Improved Ni/3C-SiC contacts by effective contact area and conductivity increases at the nanoscale

Jens Eriksson, Fabrizio Roccaforte, Filippo Giannazzo, Raffaella Lo Nigro, Vito Raineri, Jean Lorenzzi, and Gabriel Ferro

Appl. Phys. Lett. 94, 112104 (2009); http://dx.doi.org/10.1063/1.3099901 (3 pages) | Cited 2 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the evolution of the electrical and structural properties of Ni/3C-SiC contacts during annealing in the temperature range of 600–950 °C. A structural analysis showed the formation of different nickel silicide phases upon annealing. A combination of transmission line model and conductive atomic force microscopy measurements demonstrated a correlation between the macroscale specific contact resistance and the nanoscale resistance, measured locally across the sample. These results further revealed that the structural evolution is accompanied by an increased uniformity of the local current distribution, indicating that an increase of the effective contact area contributes to the improvement of the contact properties.
Show PACS
73.40.Cg Contact resistance, contact potential
81.40.Gh Other heat and thermomechanical treatments
72.20.Fr Low-field transport and mobility; piezoresistance
68.55.ag Semiconductors
68.37.Ps Atomic force microscopy (AFM)
73.40.Ns Metal-nonmetal contacts

Spatially resolved doping concentration measurement in semiconductors via spin noise spectroscopy

M. Römer, J. Hübner, and M. Oestreich

Appl. Phys. Lett. 94, 112105 (2009); http://dx.doi.org/10.1063/1.3098074 (3 pages) | Cited 7 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose and demonstrate spin noise spectroscopy as an efficient, noncontact method to measure doping concentrations in semiconductors with high accuracy and high spatial resolution. In a proof of concept study, two different doping levels in a silicon-doped GaAs stack are depth resolved with a relative accuracy of up to 5% and a spatial accuracy better than 50 μm. The method promises three-dimensional doping measurements in direct semiconductors with submicrometer resolution even at extremely low doping concentrations.
Show PACS
61.72.uj III-V and II-VI semiconductors
72.70.+m Noise processes and phenomena
72.25.-b Spin polarized transport

Graphitization process of SiC(0001) studied by electron energy loss spectroscopy

T. Langer, H. Pfnür, H. W. Schumacher, and C. Tegenkamp

Appl. Phys. Lett. 94, 112106 (2009); http://dx.doi.org/10.1063/1.3100776 (3 pages) | Cited 9 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electron energy loss spectroscopy (EELS) is used to study the transition from the buffer layer to the first graphene layers during graphitization of SiC(0001). Graphene growth is controlled and correlated with spot profile analysis in low energy electron diffraction and x-ray photoelectron spectroscopy. In the EELS data both electronic transitions and plasmon losses are sensitive to the interface. The collective in-plane excitations show a characteristic blueshift upon graphitization, while single electron transitions with dipole moments along the surface normal are suppressed for the buffer layer. These dependencies can be used to control the number of epitaxially grown graphene layers.
Show PACS
71.30.+h Metal-insulator transitions and other electronic transitions
68.55.-a Thin film structure and morphology
68.35.bg Semiconductors
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
79.20.Uv Electron energy loss spectroscopy
79.60.Jv Interfaces; heterostructures; nanostructures

Pulse width controlled resistivity switching at room temperature in Bi0.8Sr0.2MnO3

A. Rebello and R. Mahendiran

Appl. Phys. Lett. 94, 112107 (2009); http://dx.doi.org/10.1063/1.3093673 (3 pages) | Cited 9 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report pulsed as well as direct current/voltage induced electroresistance in Bi0.8Sr0.2MnO3 at room temperature. It is shown that bilevel and multilevel resistivity switching can be induced by a sequence of pulses of varying pulse width at a fixed voltage amplitude. Resistivity increases abruptly (≈55% at 300 K) upon reducing pulse width from 100 to 25 ms for a fixed electric field (E = 2 V/cm2) of 200 ms pulse period. The resistivity switching is accompanied by a periodic change in temperature, which alone cannot explain the magnitude of the resistivity change.
Show PACS
72.60.+g Mixed conductivity and conductivity transitions
72.80.Ga Transition-metal compounds
72.20.Fr Low-field transport and mobility; piezoresistance

Growth of AlGaN/GaN heterojunction field effect transistors on semi-insulating GaN using an AlGaN interlayer

Z. Chen (陈振), Y. Pei (裴轶), S. Newman, R. Chu (储荣明), D. Brown, R. Chung, S. Keller, S. P. Denbaars, S. Nakamura, and U. K. Mishra

Appl. Phys. Lett. 94, 112108 (2009); http://dx.doi.org/10.1063/1.3103210 (3 pages) | Cited 10 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Semi-insulating (SI) GaN layers were grown on 4H-SiC substrates by inserting an AlGaN layer between the AlN buffer and the GaN layer. Secondary ion mass spectroscopy measurements showed that the AlGaN layer prevented Si from diffusing from the substrate into the GaN layer. X-ray diffraction and atomic force microscopy analyses showed that an optimized AlGaN interlayer does not degrade the crystal quality or surface morphology of the SI GaN. The room temperature mobility of an AlGaN/GaN heterostructure using this SI GaN was 2200 cm2/V s. High electron mobility transistors (HEMTs) with 0.65 μm long gates were also fabricated on these SI GaN buffers. A power density of 19.0 W/mm with a power added efficiency of 48% was demonstrated at 10 GHz at a drain bias of 78 V. These HEMTs also exhibited sharp pinch off, low leakage, and negligible dispersion.
Show PACS
85.30.Tv Field effect devices
68.37.Ps Atomic force microscopy (AFM)
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
72.20.Fr Low-field transport and mobility; piezoresistance

Observation of stacking faults formed during homoepitaxial growth of p-type 4H-SiC

Ho Keun Song, Jeong Hyun Moon, Hyeong Joon Kim, and Mehran Mehregany

Appl. Phys. Lett. 94, 112109 (2009); http://dx.doi.org/10.1063/1.3089697 (3 pages) | Cited 1 time

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Threading dislocations and their transformation into stacking faults (SFs) are observed in p-type 4H-SiC epitaxial layers by high voltage transmission electron microscope. Homoepitaxial growth and in situ aluminum doping of 4H-SiC epitaxial layers are carried out using the organosilicon precursor bistrimethylsilylmethane (C7H20Si2 and the metal-organic precursor trimethylaluminum (C3H9Al), and the free hole concentration of the most heavily aluminum-doped epitaxial layers is >1021 cm−3. Threading dislocations are formed at the interface between the epitaxial layer and the substrate. However, the density of these threading dislocations decreases toward the epitaxial layer surface with their transformations to SFs.
Show PACS
61.72.Lk Linear defects: dislocations, disclinations
61.72.up Other materials
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
72.80.Jc Other crystalline inorganic semiconductors

Nonvolatile memories using deep traps formed in Al2O3 by metal ion implantation

Min Choul Kim, Seung Hui Hong, Hye Ryong Kim, Sung Kim, Suk-Ho Choi, R. G. Elliman, and S. P. Russo

Appl. Phys. Lett. 94, 112110 (2009); http://dx.doi.org/10.1063/1.3097799 (3 pages) | Cited 2 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the feasibility of an approach to nonvolatile memory (NVM) that exploits charge trapping at deep-energy levels formed in Al2O3 by metal doping. Our calculations show that V and Nb are expected to form such deep energy levels in the band gap of Al2O3. To demonstrate the effectiveness of this approach these metal ions were ion-implanted into test structures based on an Al2O3 trapping layer. Several structural analysis techniques and photocurrent spectroscopy show that the doped metal ions are located close to the Al2O3/SiO2 interface and exhibit characteristics consistent with some of the deep levels predicted in calculations. The resulting test devices are shown to exhibit promising NVM characteristics.
Show PACS
84.30.Sk Pulse and digital circuits
85.40.Ry Impurity doping, diffusion and ion implantation technology

Carrier mobility in a polar semiconductor measured by an optical pump-probe technique

Muneaki Hase

Appl. Phys. Lett. 94, 112111 (2009); http://dx.doi.org/10.1063/1.3103275 (3 pages) | Cited 4 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultrafast dephasing of the plasmonlike longitudinal optical phonon-plasmon coupled (LOPC) mode in highly doped n-GaAs has been investigated by using a femtosecond optical pump-probe technique with 40 THz bandwidth as a function of photodoping levels. The direct measurement of plasmon damping with the help of a wavelet analysis enables us to extract carrier (electron) mobility, which decreases with increasing the photodoping levels. It is found that the mobility is suppressed at high photodoping levels due to electron-hole scattering, while it is enhanced near a critical density, being plausibly attributed to the strong coherent coupling of the LO phonon with the plasmon.
Show PACS
73.61.Ey III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics
61.72.U- Doping and impurity implantation
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
72.20.Fr Low-field transport and mobility; piezoresistance

Local structure and conduction mechanism in amorphous In–Ga–Zn–O films

Deok-Yong Cho, Jaewon Song, Kwang Duk Na, Cheol Seong Hwang, Jong Han Jeong, Jae Kyeong Jeong, and Yeon-Gon Mo

Appl. Phys. Lett. 94, 112112 (2009); http://dx.doi.org/10.1063/1.3103323 (3 pages) | Cited 17 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The local structures of amorphous In–Ga–Zn–O (InGaZnO4 and In2Ga2ZnO7) films were examined by x-ray absorption spectroscopy and fine structure analysis. The local metal-oxygen coordination in both films indicated bipyramidal GaO5, ZnO5, and trigonal InO6 clusters. Further analyses showed splitting of the Zn–O bond length suggesting distortion of the ZnO5 cluster, which evidenced the existence of localized holes in the Zn atoms. In combination with the abundance of In 5s electrons, this shows that the In–Zn hopping interactions contribute to electrical conduction.
Show PACS
71.23.Cq Amorphous semiconductors, metallic glasses, glasses
73.61.Jc Amorphous semiconductors; glasses
73.50.Dn Low-field transport and mobility; piezoresistance
78.70.Dm X-ray absorption spectra
71.70.-d Level splitting and interactions

Solid phase epitaxy of amorphous Ge on Si in N2 atmosphere

R. R. Lieten, S. Degroote, M. Leys, N. E. Posthuma, and G. Borghs

Appl. Phys. Lett. 94, 112113 (2009); http://dx.doi.org/10.1063/1.3098075 (3 pages) | Cited 4 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a straightforward and economical way to obtain smooth germanium layers of high quality on silicon. Thin amorphous germanium layers deposited by plasma enhanced chemical vapor deposition on Si(111) substrates are transformed into single crystalline and smooth layers by solid phase epitaxy in N2 atmosphere. The crystal orientation of the substrate has a clear influence on the crystal quality. This is most likely due to a different growth mode, namely, layer-by-layer for Si(111) and three-dimensional growth for Si(001). The amorphous germanium layer can roughen during annealing due to mobile atoms on the surface. This can be effectively suppressed by annealing in N2 ambient. Electrical measurements show high charge mobility.
Show PACS
81.05.Cy Elemental semiconductors
81.05.Gc Amorphous semiconductors
81.15.Np Solid phase epitaxy; growth from solid phases
68.55.ag Semiconductors
61.72.Cc Kinetics of defect formation and annealing
73.61.Cw Elemental semiconductors
back to top
RSS Feeds

Generation of spin-wave pulse trains by current-controlled magnetic mirrors

A. A. Serga, T. Neumann, A. V. Chumak, and B. Hillebrands

Appl. Phys. Lett. 94, 112501 (2009); http://dx.doi.org/10.1063/1.3098407 (3 pages) | Cited 7 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The evolution of a packet of long-wavelength, dipole-dominated spin waves trapped between two direct current-carrying wires placed on the surface of a ferrite film is observed by Brillouin light scattering. The wires act as semitransparent mirrors confining the packet. Because the spin-wave energy partially passes through these mirrors, trains of spin-wave packets are generated outside the trap. A numerical model is presented and applied to the case when the current in the wires is dynamically controlled. The dynamic control of the mirror reflectivity provides new functionalities interesting for the field of spin-wave logic like that of a spin-wave memory cell.
Show PACS
75.50.Gg Ferrimagnetics
75.30.Ds Spin waves
75.70.Ak Magnetic properties of monolayers and thin films
78.35.+c Brillouin and Rayleigh scattering; other light scattering

Magnetic domain-wall motion by propagating spin waves

Dong-Soo Han, Sang-Koog Kim, Jun-Young Lee, Sebastian J. Hermsdoerfer, Helmut Schultheiss, Britta Leven, and Burkard Hillebrands

Appl. Phys. Lett. 94, 112502 (2009); http://dx.doi.org/10.1063/1.3098409 (3 pages) | Cited 22 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We found by micromagnetic simulations that the motion of a transverse wall (TW)–type domain wall in magnetic thin-film nanostripes can be manipulated via interaction with spin waves (SWs) propagating through the TW. The velocity of the TW motion can be controlled by changes of the frequency and amplitude of the propagating SWs. Moreover, the TW motion is efficiently driven by specific SW frequencies that coincide with the resonant frequencies of the local modes existing inside the TW structure. The use of propagating SWs, whose frequencies are tuned to those of the intrinsic TW modes, is an alternative approach for controlling TW motion in nanostripes.
Show PACS
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.50.Tt Fine-particle systems; nanocrystalline materials
75.30.Ds Spin waves

Perpendicular spin torque promotes synchronization of magnetic tunnel junction based spin torque oscillators

Yan Zhou and Johan Åkerman

Appl. Phys. Lett. 94, 112503 (2009); http://dx.doi.org/10.1063/1.3100299 (3 pages) | Cited 13 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study how the perpendicular spin transfer torque term (bj), present in magnetic tunneling junctions (MTJs), affects the synchronization of serially connected MTJ-based spin torque oscillators (MTJ-STOs). We find that bj modifies the intrinsic preferred I-V phase shift in single MTJ-STO in such a way that serially connected MTJ-STOs synchronize much more readily without the need for additional circuitry to change the I-V phase. This result strongly suggests that synchronization of serially connected MTJ-STOs should be significantly more straightforward than the previously attempted serial synchronization of giant magnetoresistance based STOs (GMR-STOs).
Show PACS
85.70.Kh Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
75.70.Ak Magnetic properties of monolayers and thin films
84.30.Ng Oscillators, pulse generators, and function generators
84.40.-x Radiowave and microwave (including millimeter wave) technology

High magnetoresistance tunnel junctions with Mg–B–O barriers and Ni–Fe–B free electrodes

J. C. Read, Judy J. Cha, William F. Egelhoff, Jr., H. W. Tseng, P. Y. Huang, Y. Li, David A. Muller, and R. A. Buhrman

Appl. Phys. Lett. 94, 112504 (2009); http://dx.doi.org/10.1063/1.3095595 (3 pages) | Cited 11 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The use of boron-alloyed electrodes with the radio frequency (rf) sputter deposition of MgO yields magnetic tunnel junctions (MTJs) with Mg–B–O tunnel barriers. After annealing, such MTJs can exhibit very high tunneling magnetoresistance (TMR) in the thin ( ∼ 1.0 nm) barrier regime. Scanning tunneling spectroscopy of Mg–B–O layers reveals a better defined, but smaller band gap in comparison to that of thin MgO. We produced Fe60Co20B20/Mg–B–O/Ni65Fe15B20 MTJs where after a 350 °C annealing the Ni–Fe–B free electrode crystallizes into a highly textured (001)-normal body centered cubic (bcc) crystal structure and the MTJs achieve 155% TMR.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.47.Np Metals and alloys
61.66.Dk Alloys

High-rate reactive ion etching of barium hexaferrite films using optimal CHF3/SF6 gas mixtures

Zhaohui Chen, Aria Yang, Changqing Xie, Qinghua Yang, C. Vittoria, and V. G. Harris

Appl. Phys. Lett. 94, 112505 (2009); http://dx.doi.org/10.1063/1.3099884 (3 pages) | Cited 5 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The high-rate reactive ion etching of c-axis oriented quasi-single-crystal barium hexaferrite (BaM) films, deposited on 6-H silicon carbide (0001) substrates, has been demonstrated. Arrays of BaM columns, having diameters of 1–4 μm and sharp vertical walls, were etched from BaM films at rates as high as 75 nm/min using an optimized sulfur hexafluoride and methyl trifluoride (SF6:CHF3, 3:1) gas mixture. Lateral features as small as 43 nm were fabricated and imaged.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Gg Ferrimagnetics
Author Select

Anisotropy of the superconducting transport properties of the LaAlO3/SrTiO3 interface

N. Reyren, S. Gariglio, A. D. Caviglia, D. Jaccard, T. Schneider, and J.-M. Triscone

Appl. Phys. Lett. 94, 112506 (2009); http://dx.doi.org/10.1063/1.3100777 (3 pages) | Cited 14 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The superconducting transport properties of the conducting LaAlO3/SrTiO3 interface have been investigated in perpendicular and parallel magnetic fields. A large anisotropy in the transport properties is measured and the two-dimensional nature of the superconducting gas is confirmed. Analyses of the resistance versus temperature and magnetic field, as well as of the correlation length as a function of the magnetic field close to the superconducting critical temperature (about 200 mK), yield an estimate of ∼ 10 nm for the superconducting layer thickness.
Show PACS
74.25.F- Transport properties
74.10.+v Occurrence, potential candidates
74.78.-w Superconducting films and low-dimensional structures
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close