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

24 Aug 2009

Volume 95, Issue 8, Articles (08xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 95, 082507 (2009); http://dx.doi.org/10.1063/1.3186782 (3 pages)

Sang-Koog Kim, Ki-Suk Lee, and Dong-Soo Han
Enlarge Image | Read More
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Influence of the interface on the electronic channel switching of a Fe–Ag thin film on a Si substrate

J. Alonso, M. L. Fdez-Gubieda, G. Sarmiento, J. M. Barandiarán, A. Svalov, I. Orue, J. Chaboy, L. Fernández Barquín, C. Meneghini, T. Neisius, and N. Kawamura

Appl. Phys. Lett. 95, 082103 (2009); http://dx.doi.org/10.1063/1.3205124 (3 pages) | Cited 1 time

Online Publication Date: 25 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
FexAg100−x granular thin films, being 20<x<70, were prepared by pulsed laser deposition. The thermal evolution of the electric resistance shows a dramatic drop in the range of 200<T<300 K, completely reversible with temperature and associated to a current switching between the granular thin film and its Si substrate. High resolution transmission electron microscopy measurements have revealed an amorphous interface between the thin film and the substrate, and x-ray absorption spectroscopy studies have demonstrated an electronic localization associated to the Fe atoms in this interface, which is intrinsically responsible for the current switching.
Show PACS
73.40.Ns Metal-nonmetal contacts
73.61.At Metal and metallic alloys
68.35.Ct Interface structure and roughness
78.70.Dm X-ray absorption spectra
68.47.Fg Semiconductor surfaces

Conductance through a single impurity in the metallic zigzag carbon nanotube

Po-Yao Chang and Hsiu-Hau Lin

Appl. Phys. Lett. 95, 082104 (2009); http://dx.doi.org/10.1063/1.3213546 (3 pages) | Cited 1 time

Online Publication Date: 25 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the conductance through a single impurity in the metallic zigzag carbon nanotube and find that it sensitively depends on the impurity strength and the bias voltage. The interplay between the current-carrying scattering states and the evanescent modes lead to rich phenomena including resonant backward scattering, perfect tunneling, and charge accumulations. In addition to the Friedel sum rule, we also find an exact relation between the conductance and the scattering phase. Finally, relevance of our findings to the realistic transport in carbon nanotubes is discussed.
Show PACS
73.63.Fg Nanotubes
73.40.Gk Tunneling
61.72.S- Impurities in crystals

Ultralow noise field-effect transistor from multilayer graphene

Atindra Nath Pal and Arindam Ghosh

Appl. Phys. Lett. 95, 082105 (2009); http://dx.doi.org/10.1063/1.3206658 (3 pages) | Cited 15 times

Online Publication Date: 25 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present low-frequency electrical resistance fluctuations, or noise, in graphene-based field-effect devices with varying number of layers. In single-layer devices, the noise magnitude decreases with increasing carrier density, which behaved oppositely in the devices with two or larger number of layers accompanied by a suppression in noise magnitude by more than two orders in the latter case. This behavior can be explained from the influence of external electric field on graphene band structure, and provides a simple transport-based route to isolate single-layer graphene devices from those with multiple layers.
Show PACS
85.30.Tv Field effect devices
73.61.Wp Fullerenes and related materials

Self-cleaning and surface recovery with arsine pretreatment in ex situ atomic-layer-deposition of Al2O3 on GaAs

Cheng-Wei Cheng, John Hennessy, Dimitri Antoniadis, and Eugene A. Fitzgerald

Appl. Phys. Lett. 95, 082106 (2009); http://dx.doi.org/10.1063/1.3213545 (3 pages) | Cited 13 times

Online Publication Date: 26 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Annealing native oxide covered GaAs samples in Arsine(AsH3) prior to atomic-layer-deposition of Al2O3 with trimethyaluminum (TMA) and isopropanol (IPA) results in capacitance-voltage (C-V) characteristics of the treated samples that resemble the superior C-V characteristics of p-type GaAs grown by an in situ metal-organic chemical vapor deposition process. Both TMA and IPA show self-cleaning effect on removing the native oxide in ex situ process, little evidence of a native oxide was observed with high resolution transmission electron microscopy at the Al2O3/GaAs interface. The discrepancy in the C-V characteristics was observed in in situ p- and n-type GaAs samples.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
61.72.Cc Kinetics of defect formation and annealing
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Multiple conducting carriers generated in LaAlO3/SrTiO3 heterostructures

S. S. A. Seo, Z. Marton, W. S. Choi, G. W. J. Hassink, D. H. A. Blank, H. Y. Hwang, T. W. Noh, T. Egami, and H. N. Lee

Appl. Phys. Lett. 95, 082107 (2009); http://dx.doi.org/10.1063/1.3213390 (3 pages) | Cited 30 times

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have found that there is more than one type of conducting carriers generated in LaAlO3/SrTiO3 heterostructures by comparing the sheet carrier density and mobility from optical transmission spectroscopy with those from dc-transport measurements. When multiple types of carriers exist, optical characterization dominantly reflects the contribution from the high-density carriers whereas dc-transport measurements may exaggerate the contribution of the high-mobility carriers even though they are present at low density. Since the low-temperature mobility determined by dc-transport in the LaAlO3/SrTiO3 heterostructures is much higher than that extracted by optical method, we attribute the origin of high-mobility transport to the low-density conducting carriers.
Show PACS
72.20.Ee Mobility edges; hopping transport
72.20.My Galvanomagnetic and other magnetotransport effects
72.80.Sk Insulators

Spin-orbit engineering of semiconductor heterostructures: A spin-sensitive quantum-phase shifter

T. L. Hoai Nguyen, Henri-Jean Drouhin, Jean-Eric Wegrowe, and Guy Fishman

Appl. Phys. Lett. 95, 082108 (2009); http://dx.doi.org/10.1063/1.3211118 (3 pages)

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In noncentrosymmetric semiconductors with zinc-blende structure grown along the [110] crystallographic direction, electrons with up- and down-spins undergo different quantum-phase shifts upon tunneling, which can be viewed as resulting from spin precession around a complex magnetic field. There is no spin filtering but a pure spin dephasing. The phase shift of the transmitted wave is proportional to the overall barrier-material thickness. We show that a device incorporating a number of resonant tunnel barriers constitutes an efficient quantum-phase shifter.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
84.30.Qi Modulators and demodulators; discriminators, comparators, mixers, limiters, and compressors
73.40.Gk Tunneling
Author Select

Control of electric current by graphene edge structure engineering

Masayuki Yamamoto and Katsunori Wakabayashi

Appl. Phys. Lett. 95, 082109 (2009); http://dx.doi.org/10.1063/1.3206915 (3 pages) | Cited 8 times

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In graphene nanoribbon junctions, the nearly perfect transmission occurs in some junctions while the zero conductance dips due to antiresonance appear in others. We have classified the appearance of zero conductance dips for all combinations of ribbon and junction edge structures. These transport properties do not attribute to the whole junction structure but the partial corner edge structure, which indicates that one can control the electric current simply by cutting a part of nanoribbon edge. The ribbon width is expected to be narrower than 10 nm in order to observe the zero conductance dips at room temperature.
Show PACS
73.63.-b Electronic transport in nanoscale materials and structures
72.20.Fr Low-field transport and mobility; piezoresistance
61.48.De Structure of carbon nanotubes, boron nanotubes, and other related systems

Effect of gate orientation on dc characteristics of Si-doped, nonpolar AlGaN/GaN metal-oxide semiconductor high electron mobility transistors

C. Y. Chang, Yu-Lin Wang, B. P. Gila, A. P. Gerger, S. J. Pearton, C. F. Lo, F. Ren, Q. Sun, Yu. Zhang, and J. Han

Appl. Phys. Lett. 95, 082110 (2009); http://dx.doi.org/10.1063/1.3216576 (3 pages) | Cited 5 times

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
Sc2O3/AlGaN/GaN metal-oxide-semiconductor (MOS) high electron mobility transistors were fabricated on (11math0) a-plane, Si-doped epitaxial layers grown by metal organic chemical vapor deposition on (1 math20) r-plane sapphire substrates. The gate finger direction was varied from parallel to the in-plane c-axis [0001] to the m-axis [1 0math0] direction perpendicular to the observed striations in surface morphology. The [0001] gate devices show lower drain-source current, mobility, and transconductance than their [1 0math0] counterparts, with a systematic dependence on gate finger direction. The symmetrical gate current-voltage characteristics and low gate current ( ∼ 3×10−9 A at ±5 V) confirm the effectiveness of the MOS gate, which is an attractive approach for these structures containing heavily Si-doped AlGaN.
Show PACS
85.30.Tv Field effect devices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
back to top
RSS Feeds

Effects of particle dipole interaction on the ac magnetically induced heating characteristics of ferrite nanoparticles for hyperthermia

Minhong Jeun, Seongtae Bae, Asahi Tomitaka, Yasushi Takemura, Ki Ho Park, Sun Ha Paek, and Kyung-Won Chung

Appl. Phys. Lett. 95, 082501 (2009); http://dx.doi.org/10.1063/1.3211120 (3 pages) | Cited 18 times

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetic particle dipole interaction was revealed as a crucial physical parameter to be considered in optimizing the ac magnetically induced heating characteristics of magnetic nanoparticles. The ac heating temperature of soft MFe2O4 (M = Mg,Ni) nanoparticles was remarkably increased from 17.6 to 94.7 °C (MgFe2O4) and from 13.1 to 103.1 °C (NiFe2O4) by increasing the particle dipole interaction energy at fixed ac magnetic field of 140 Oe and frequency of 110 kHz. The increase in “magnetic hysteresis loss” that resulted from the particle dipole interaction was the main physical reason for the significant improvement of ac heating characteristics.
Show PACS
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
87.19.Pp Biothermics and thermal processes in biology
75.50.Gg Ferrimagnetics

Magnetization relaxation and structure of CoFeGe alloys

H. Lee, Y.-H. A. Wang, C. K. A. Mewes, W. H. Butler, T. Mewes, S. Maat, B. York, M. J. Carey, and J. R. Childress

Appl. Phys. Lett. 95, 082502 (2009); http://dx.doi.org/10.1063/1.3207749 (3 pages) | Cited 12 times

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic relaxation of 10 and 50 nm thin films of (CoFe)100−xGex (0 at. % ≤ x ≤ 35 at. %) alloys was investigated by broadband ferromagnetic resonance (FMR) experiments. 10 nm thin films exhibit a significant two magnon contribution to the FMR linewidth. The 50 nm films exhibit very low damping constants of α ≈ 0.0025 and relaxation rates as low as 33 MHz in the composition range of 20 at. % ≤ x ≤ 30 at. % Ge after annealing. Structural characterization revealed B2 order for these compositions. First principles calculations confirm a pseudogap in the minority channel for B2 ordered (CoFe)75Ge25 which may cause the low damping parameters and high ΔRA in CoFeGe based current perpendicular to the plane giant magnetoresistance spin valves.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
68.55.-a Thin film structure and morphology
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
81.40.Gh Other heat and thermomechanical treatments
75.50.Bb Fe and its alloys
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields

A large magnetoinductance effect in La0.67Ba0.33MnO3

V. B. Naik, A. Rebello, and R. Mahendiran

Appl. Phys. Lett. 95, 082503 (2009); http://dx.doi.org/10.1063/1.3212730 (3 pages) | Cited 1 time

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report four probe impedance (Z = R+iX) of La0.67Ba0.33MnO3 at f = 100 kHz under different dc bias magnetic fields. The ac resistance (R) exhibits a peak around TP = 325 K which is accompanied by a rapid increase and a peak in the reactance (X) in a zero field. The magnetoreactance (ΔX/X) exhibits a sharp peak close to TP and its magnitude ( ≈ 60% in H = 1 kG) exceeds that of the ac magnetoresistance (ΔR/R = 5%). It is suggested that the magnetoreactance arises from changes in the self inductance of the sample rather than the capacitance.
Show PACS
75.47.Lx Magnetic oxides
75.50.Dd Nonmetallic ferromagnetic materials

Atomically resolved Larmor frequency detection on Si(111)-7×7 oxide surface

Yasuyuki Sainoo, Hironari Isshiki, Syed Mohammad Fakruddin Shahed, Tsuyoshi Takaoka, and Tadahiro Komeda

Appl. Phys. Lett. 95, 082504 (2009); http://dx.doi.org/10.1063/1.3204688 (3 pages) | Cited 2 times

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate that the electron spin resonance–scanning tunneling microscope can detect the Larmor frequency of a single spin with the atomic scale resolution on the oxygen-adsorbed Si(111)-7×7 surface. The spin signal from the Si dangling bond was detected on the oxygen-induced bright Si adatom with the Larmor frequency corresponding to g ∼ 2.00. However, no peak was detected on the dark adatom that is tied with an oxygen atom and the dangling bond is disappeared.
Show PACS
07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
07.79.Cz Scanning tunneling microscopes
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)

Microwave-assisted magnetization reversal in a Co/Pd multilayer with perpendicular magnetic anisotropy

Yukio Nozaki, Naoyuki Narita, Terumitsu Tanaka, and Kimihide Matsuyama

Appl. Phys. Lett. 95, 082505 (2009); http://dx.doi.org/10.1063/1.3213559 (3 pages) | Cited 19 times

Online Publication Date: 26 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Microwave-assisted magnetization reversal in a rectangle of a Co/Pd multilayer with a perpendicular magnetic anisotropy is examined using vector network analyzer ferromagnetic resonance (FMR) spectroscopy. A microwave field is applied along the in-plane direction of the rectangle together with a negative dc easy-axis field smaller than the coercive field. Broadening or splitting of the peak profile in the FMR spectrum suggesting the formation of multidomain structure appears after the microwave field is applied. The dominance of microwave-assisted nucleation of magnetization is supported by the frequency dependence of the probability with which the multidomain structure appears.
Show PACS
75.60.Jk Magnetization reversal mechanisms
75.30.Gw Magnetic anisotropy
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
78.70.Gq Microwave and radio-frequency interactions
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.50.Cc Other ferromagnetic metals and alloys
68.55.A- Nucleation and growth

Thermal-magnetic noise measurement of spin-torque effects on ferromagnetic resonance in MgO-based magnetic tunnel junctions

Y. Guan, J. Z. Sun, X. Jiang, R. Moriya, L. Gao, and S. S. P. Parkin

Appl. Phys. Lett. 95, 082506 (2009); http://dx.doi.org/10.1063/1.3212870 (3 pages) | Cited 6 times

Online Publication Date: 26 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermal-magnetic noise at ferromagnetic resonance (T-FMR) can be used to measure magnetic perpendicular anisotropy of nanoscale magnetic tunnel junctions (MTJs). For this purpose, T-FMR measurements were conducted with an external magnetic field up to 14 kOe applied perpendicular to the film surface of MgO-based MTJs under a dc bias. The observed frequency-field relationship suggests that a 20 Å CoFeB free layer has an effective demagnetization field much smaller than the intrinsic bulk value of CoFeB, with 4πMeff = 6.1±0.3 kOe. This value is consistent with the saturation field obtained from magnetometry measurements on extended films of the same CoFeB thickness. In-plane T-FMR on the other hand shows less consistent results for the effective demagnetization field, presumably due to excitations of more complex modes. These experiments suggest that the perpendicular T-FMR is preferred for quantitative magnetic characterization of nanoscale MTJs.
Show PACS
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.75.-c Magnetic properties of nanostructures
75.70.Ak Magnetic properties of monolayers and thin films

A gigahertz-range spin-wave filter composed of width-modulated nanostrip magnonic-crystal waveguides

Sang-Koog Kim, Ki-Suk Lee, and Dong-Soo Han

Appl. Phys. Lett. 95, 082507 (2009); http://dx.doi.org/10.1063/1.3186782 (3 pages) | Cited 16 times

Online Publication Date: 26 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We found a robust magnonic-crystal waveguide structure for use as an efficient gigahertz-range spin-wave filter that passes only spin waves of chosen narrow band frequencies and filters out the other frequencies. The structure consists of the serial combinations of various width modulations with different periodicities and motifs in planar-patterned thin-film nanostrips composed of a single soft magnetic material. The observed magnonic band gaps result from both the translation symmetry of the one-dimensional width modulation and the higher-quantized width-mode spin waves excited from scattering at the periodic edge-steps of the width modulation. This work brings us one step closer to practical implementations of spin waves in information transmission and processing devices.
Show PACS
84.30.Vn Filters
84.40.Az Waveguides, transmission lines, striplines
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Martensitic transformation and magnetic field-induced strain in Fe–Mn–Ga shape memory alloy

T. Omori, K. Watanabe, R. Y. Umetsu, R. Kainuma, and K. Ishida

Appl. Phys. Lett. 95, 082508 (2009); http://dx.doi.org/10.1063/1.3213353 (3 pages) | Cited 11 times

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Martensitic and magnetic properties of Fe–Mn–Ga single and polycrystalline alloys were investigated. It was found that Fe–Mn–Ga alloys exhibit martensitic transformation from the paramagnetic L21 Heusler parent phase to the ferromagnetic L10 martensite phase. The martensitic transformation temperatures increased by about 20 K by the application of a magnetic field of 7 T, and a metamagnetic phase transition was observed. In addition, a magnetic field-induced strain of 0.6% associated with magnetic field-induced forward transformation was confirmed in an Fe43Mn28Ga29 single crystal.
Show PACS
81.30.Kf Martensitic transformations
75.50.Bb Fe and its alloys
75.80.+q Magnetomechanical effects, magnetostriction
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.20.-g Diamagnetism, paramagnetism, and superparamagnetism

Granular magnetoresistance in cobalt/poly (3-hexylthiophene, 2, 5-diyl) hybrid thin films prepared by a wet chemical method

Tianlong Wen, Dan Liu, Christine K. Luscombe, and Kannan M. Krishnan

Appl. Phys. Lett. 95, 082509 (2009); http://dx.doi.org/10.1063/1.3213561 (3 pages) | Cited 3 times

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cobalt/poly (3-hexylthiophene, 2, 5-diyl) (P3HT) hybrid thin films were prepared by a wet chemical method. Their microstructure consists of a nanoscale mixture of a crystalline P3HT matrix, interspersed with amorphous P3HT regions containing the cobalt nanoparticles. Magnetic and transport measurements are consistent with this microstructure and the temperature dependence of the resistance of these hybrid systems is well-fitted (R2 = 0.9993) to the fluctuation induced tunneling model. Moreover, by applying a magnetic field, a magnetoresistance ratio of 3% was observed in 17 vol % Co hybrid films at 10 K.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
68.55.ag Semiconductors
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Cc Other ferromagnetic metals and alloys
72.20.My Galvanomagnetic and other magnetotransport effects
back to top
RSS Feeds

Multiferroic properties of layer-structured Bi5Fe0.5Co0.5Ti3O15 ceramics

Xiangyu Mao, Wei Wang, Xiaobing Chen, and Yalin Lu

Appl. Phys. Lett. 95, 082901 (2009); http://dx.doi.org/10.1063/1.3213344 (3 pages) | Cited 32 times

Online Publication Date: 25 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Layer-structured, single phase Bi5Fe0.5Co0.5Ti3O15 ceramics was synthesized following a multicalcination procedure. Magnetic moment increases more than three times by substituting half Fe sites by Co ions. The material exhibits an Aurivillius phase with a four-layer unit cell structure, and presents a remarkable coexistence of ferroelectricity and ferromagnetism above room temperature. The measured 2Pr and 2Mr are 13 μC/cm2 and 7.8 memu/g, respectively. The material’s magnetic behavior below 275 °C is relaxationlike and its magnetic Curie temperature is ∼ 345 °C.
Show PACS
75.80.+q Magnetomechanical effects, magnetostriction
77.80.-e Ferroelectricity and antiferroelectricity
75.30.Cr Saturation moments and magnetic susceptibilities
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
75.50.Dd Nonmetallic ferromagnetic materials
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

Electrical properties of ZnO–BaTiO3–ZnO heterostructures with asymmetric interface charge distribution

V. M. Voora, T. Hofmann, M. Brandt, M. Lorenz, N. Ashkenov, M. Grundmann, and M. Schubert

Appl. Phys. Lett. 95, 082902 (2009); http://dx.doi.org/10.1063/1.3211914 (3 pages) | Cited 10 times

Online Publication Date: 25 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on capacitance-voltage, current-voltage, Sawyer–Tower, and transient current switching measurements for a ZnO–BaTiO3–ZnO heterostructure deposited on (001) silicon by using pulsed laser deposition. The triple-layer structure reveals asymmetric capacitance- and current-voltage hysteresis and cycling-voltage dependent Sawyer–Tower polarization drift. We explain our findings by coupling of the ferroelectric (BaTiO3) and piezoelectric (ZnO) interface charges and parallel polarization orientation of the ZnO layers causing asymmetric space charge region formation under positive and negative bias. The transient current characteristics suggest use of this structure as nonvolatile memory device.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
77.55.-g Dielectric thin films
81.15.Fg Pulsed laser ablation deposition
77.80.-e Ferroelectricity and antiferroelectricity
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.22.Ej Polarization and depolarization

Left-handed behavior of strontium-doped lanthanum manganite in the millimeter waveband

M. K. Khodzitsky, T. V. Kalmykova, S. I. Tarapov, D. P. Belozorov, A. M. Pogorily, A. I. Tovstolytkin, A. G. Belous, and S. A. Solopan

Appl. Phys. Lett. 95, 082903 (2009); http://dx.doi.org/10.1063/1.3204004 (3 pages) | Cited 6 times

Online Publication Date: 26 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Left-handed behavior of strontium-doped lanthanum manganite was revealed in the millimeter waveband. The bulk specimen of La1−xSrxMnO3, was used as a boundary medium for one-dimensional photonic crystal. In the absence of magnetic field known Tamm peak appears in the forbidden zone of photonic crystal indicating that manganite is a single negative medium (negative permittivity). In the presence of external magnetic field somewhat above frequency of ferromagnetic resonance the additional (field sensitive) transparency peak appears in photonic crystal forbidden zone, indicating that manganite becomes double negative medium (negative permittivity and permeability). Model theoretical calculations corroborate the experimental findings.
Show PACS
78.70.Gq Microwave and radio-frequency interactions
77.22.Ch Permittivity (dielectric function)
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
42.70.Qs Photonic bandgap materials

Second harmonic generation microscopic observations of a multiferroic BiFeO3 single crystal

Hiroko Yokota, Raphael Haumont, Jean-Michel Kiat, Hiroto Matsuura, and Yoshiaki Uesu

Appl. Phys. Lett. 95, 082904 (2009); http://dx.doi.org/10.1063/1.3212729 (3 pages) | Cited 1 time

Online Publication Date: 27 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Anisotropy of the optical second harmonic generation (SHG) in a multiferroic BiFeO3 single crystal is observed by an SHG microscope. Polarization dependences of SH intensities are measured in several polarization configurations of the incident and SH waves to determine the magnitude and sign of polar i-type SHG tensor components. To obtain proper values of these SHG tensors, the effects of the interference term and wave number mismatch are taken into account in these analyses. d24 component is 15 times larger than d32 and this result is essentially different from the thin film case.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.25.Ja Polarization
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

Local bonding effect on the defect states of oxygen vacancy in amorphous HfSiO4

Hyeon-Kyun Noh, Byungki Ryu, Eun-Ae Choi, Junhyeok Bang, and K. J. Chang

Appl. Phys. Lett. 95, 082905 (2009); http://dx.doi.org/10.1063/1.3216058 (3 pages) | Cited 1 time

Online Publication Date: 28 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We perform first-principles calculations to investigate the defect properties of O vacancies in amorphous HfSiO4. For atomic models generated from molecular dynamics simulations, we find that O vacancies, which have only Hf atoms or a mixture of Hf and Si in the neighborhood, behave as charge trap centers, similar to those in HfO2. On the other hand, O vacancies surrounded by only Si atoms are energetically most favorable and have very high trap energies for both electron and hole carriers. Thus, these defects are suggested to be responsible for the reduction of threshold voltage instability.
Show PACS
61.50.Lt Crystal binding; cohesive energy
61.72.jd Vacancies
71.15.Pd Molecular dynamics calculations (Car-Parrinello) and other numerical simulations
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
71.55.Jv Disordered structures; amorphous and glassy solids
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
back to top
RSS Feeds

Electrical control of singlet-triplet entanglement in lateral quantum dot molecules

Fanyao Qu, G. L. Iório, V. Lopez-Richard, and G. E. Marques

Appl. Phys. Lett. 95, 083101 (2009); http://dx.doi.org/10.1063/1.3210786 (3 pages) | Cited 5 times

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study effects of spin-orbit coupling and electron-electron correlation, which can be electrically tuned, on the singlet-triplet entanglement in double lateral quantum dots charged with two electrons. We have found that the magnetic character of a double-dot system can be changed from diamagnetic to paramagnetic, only by adjusting the strength of spin-orbit coupling. Coulomb interaction leads to an unusual singlet-triplet energy splitting, accompanied by a shift of this transition energy to the lower magnetic field side in the energy spectrum.
Show PACS
73.21.La Quantum dots
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
75.20.Ck Nonmetals
75.50.Pp Magnetic semiconductors

Temperature dependence of electronic energy transfer in PbS quantum dot films

Wei Lü, Itaru Kamiya, Masao Ichida, and Hiroaki Ando

Appl. Phys. Lett. 95, 083102 (2009); http://dx.doi.org/10.1063/1.3213349 (3 pages) | Cited 7 times

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Colloidal PbS quantum dots dispersed as close-packed film and in polystyrene (PS) matrix are prepared and photoluminescence (PL) spectra are measured in the temperature range of 5–300 K. The integrated PL intensity of the close-packed film increases as the temperature is raised from 5 to 120 K, and then decreases to 300 K, while that of the PS film decreases monotonously. This abnormal behavior of the close-packed film can be explained by a thermally activated electronic energy transfer model, which is supported by time resolved PL measurements.
Show PACS
73.63.Kv Quantum dots
73.61.Le Other inorganic semiconductors
78.66.Li Other semiconductors
78.55.Hx Other solid inorganic materials
68.55.ag Semiconductors
73.21.La Quantum dots

Fabrication of graphene layers from multiwalled carbon nanotubes using high dc pulse

Woo Sik Kim, Sook Young Moon, Sin Young Bang, Bong Geun Choi, Heon Ham, Tohru Sekino, and Kwang Bo Shim

Appl. Phys. Lett. 95, 083103 (2009); http://dx.doi.org/10.1063/1.3213350 (3 pages) | Cited 13 times

Online Publication Date: 24 August 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Graphene layers are fabricated from multiwalled carbon nanotubes (MWCNTs) with a high direct current pulse through a pulsed current sintering process. We confirm the transformation of the structure from MWCNTs to graphene layers. Graphene layers are analyzed by field emission scanning electron microscopy, high resolution transmission electron microscopy, high resolution Raman, and x-ray diffraction.
Show PACS
81.05.U- Carbon/carbon-based materials
81.05.ub Fullerenes and related materials
81.16.-c Methods of micro- and nanofabrication and processing
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
78.30.Na Fullerenes and related materials
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close