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

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Next Issue

6 Jul 2009

Volume 95, Issue 1, Articles (01xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 95, 013107 (2009); http://dx.doi.org/10.1063/1.3167775 (3 pages)

T. Y. Tsai, C. Y. Lee, N. H. Tai, and W. H. Tuan
Enlarge Image | Read More
Page 2 of 5 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Crystal symmetry breaking of wurtzite to orthorhombic in nonpolar a-ZnO epifilms

C. C. Kuo, W.-R. Liu, W. F. Hsieh, C.-H. Hsu, H. C. Hsu, and L. C. Chen

Appl. Phys. Lett. 95, 011905 (2009); http://dx.doi.org/10.1063/1.3159470 (3 pages) | Cited 7 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Crystal symmetry breaking of wurtzite C6V to orthorhombic C2V due to in-plane anisotropic strain was investigated for nonpolar (11math0) ZnO epifilms grown on the R-sapphire. X-ray diffraction results reveal the epilayer is subjected to a compressive strain along the polar c-axis and tensile strains along both a-[11math0] surface normal and in-plane p-[1math00] axis. The polarized Raman spectra of E2 modes reveal violation of the C6V selection rules. Oppositely, the C2V configuration satisfies the selection rules for the Raman modes. The observed E1 and E2 bands in polarized optical reflection and photoluminescence spectra confirm the anisotropic strain causes the structure change to the orthorhombic one.
Show PACS
78.55.Et II-VI semiconductors
78.66.Hf II-VI semiconductors
61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
68.60.Bs Mechanical and acoustical properties
78.30.Fs III-V and II-VI semiconductors

Bulk metallic glass formation near intermetallic composition through liquid quenching

W. F. Wu and Y. Li

Appl. Phys. Lett. 95, 011906 (2009); http://dx.doi.org/10.1063/1.3168411 (3 pages) | Cited 10 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Metallic glass is typically formed either by liquid quenching near deep-eutectics or by solid-state reaction near the intermetallic in center of the phase diagram. In our research, two optimum bulk glass formers are synthesized in the vicinity of the intermetallic compound of Cu–Zr system through liquid quenching. It is shown that such a pair of unique glass formation is only feasible in a narrow composition range close to but clearly separated by the intermetallic composition where both the kinetic and thermodynamic conditions for the amorphous formation are matched. The discovery of this “intermetallic glass” pair through quenching allows us to find a potentially applicable host of metallic glass systems. This is followed by a discussion on its impact on understanding the formation and physics of bulk metallic glasses.
Show PACS
61.43.Fs Glasses
64.70.pe Metallic glasses
64.70.qd Thermodynamics and statistical mechanics
81.30.Bx Phase diagrams of metals, alloys, and oxides

Crystal orientation of GaAs islands grown on SrTiO3 (001) by molecular beam epitaxy

L. Largeau, J. Cheng, P. Regreny, G. Patriarche, A. Benamrouche, Y. Robach, M. Gendry, G. Hollinger, and G. Saint-Girons

Appl. Phys. Lett. 95, 011907 (2009); http://dx.doi.org/10.1063/1.3168500 (3 pages) | Cited 2 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The growth of GaAs islands on (001)-oriented SrTiO3 (STO) substrates by molecular beam epitaxy is studied. A competition between (111)- and (001)-oriented islands takes place. It is shown that this competition is driven by the interface energy and the critical nucleation volume of the GaAs/STO system. Perspectives are proposed to control this competition in order to define reliable growth procedures for the monolithic integration of GaAs based heterostructures on crystalline STO/Si(001) templates.
Show PACS
81.10.Bk Growth from vapor
61.50.-f Structure of bulk crystals

First-principles study to obtain evidence of low interface defect density at Ge/GeO2 interfaces

Shoichiro Saito, Takuji Hosoi, Heiji Watanabe, and Tomoya Ono

Appl. Phys. Lett. 95, 011908 (2009); http://dx.doi.org/10.1063/1.3168501 (3 pages) | Cited 11 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present evidence of low defect density at Ge/GeO2 interfaces on the basis of first-principles total energy calculations. The energy advantages of atom emission from the Ge/GeO2 interface to release stress due to lattice mismatch are compared with those from the Si/SiO2 interface. The advantages of Ge/GeO2 are found to be less than those of Si/SiO2 because of the high flexibility of the bonding networks in GeO2. Thus, the suppression of Ge-atom emission during the oxidation process leads to improved electrical properties of the Ge/GeO2 interfaces.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
71.15.Nc Total energy and cohesive energy calculations
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
81.05.Cy Elemental semiconductors

Accessing nanomechanical resonators via a fast microwave circuit

Mika A. Sillanpää, Jayanta Sarkar, Jaakko Sulkko, Juha Muhonen, and Pertti J. Hakonen

Appl. Phys. Lett. 95, 011909 (2009); http://dx.doi.org/10.1063/1.3173826 (3 pages) | Cited 9 times

Online Publication Date: 8 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate how to fully electrically detect the vibrations of conductive nanomechanical resonators up to the microwave regime. We use the electrically actuated vibrations to modulate an LC tank circuit, which blocks the stray capacitance and detect the created sideband voltage by a microwave analyzer. We prove the technique up to mechanical frequencies of 200 MHz. Finally, we estimate how one could approach the quantum limit of mechanical systems.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
07.10.Cm Micromechanical devices and systems

Spectroscopic ellipsometry study of GaAs1−xBix material grown on GaAs substrate by atmospheric pressure metal-organic vapor-phase epitaxy

Nebiha Ben Sedrine, Imed Moussa, Hedi Fitouri, Ahmed Rebey, Belgacem El Jani, and Radhouane Chtourou

Appl. Phys. Lett. 95, 011910 (2009); http://dx.doi.org/10.1063/1.3167359 (3 pages) | Cited 1 time

Online Publication Date: 8 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical properties in terms of complex dielectric function of GaAs1−xBix alloys (0% ≤ x ≤ 3.7%), grown by atmospheric pressure metal-organic vapor-phase epitaxy, are determined by using room temperature spectroscopic ellipsometry. The interband transition energies in the energy range of 1.4–5.4 eV are resolved using a line shape fitting on the numerically calculated dielectric function second derivatives. The bismuth effect on the critical point parameters is then determined. We have found that, as for GaAs1−xBix alloys E0 transition, the bismuth incorporation shifts the E1, E1+Δ1, E2, and E0′ transition energies but with a lower magnitude. We also observed a root-square-like increase of the E1 broadening parameter (Γ1) with respect to the bismuth composition.
Show PACS
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.ag Semiconductors
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors

Direct gap photoluminescence of n-type tensile-strained Ge-on-Si

Xiaochen Sun, Jifeng Liu, Lionel C. Kimerling, and Jurgen Michel

Appl. Phys. Lett. 95, 011911 (2009); http://dx.doi.org/10.1063/1.3170870 (3 pages) | Cited 43 times

Online Publication Date: 9 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Room temperature direct gap photoluminescence (PL) was observed from n-type tensile-strained epitaxial Ge-on-Si. The PL intensity increases with n-type doping due to a higher electron population in the direct Γ valley as a result of increased Fermi level. The direct gap emission also increases with temperature due to thermal excitation of electrons into the direct Γ valley, exhibiting robustness to heating effects. These unique properties of direct gap emission in an indirect gap material agree with our theoretical model and make Ge a promising light emitting material in 1550 nm communication band.
Show PACS
78.66.Db Elemental semiconductors and insulators
78.55.Ap Elemental semiconductors
71.20.Mq Elemental semiconductors
68.47.Fg Semiconductor surfaces
61.72.uf Ge and Si
back to top
RSS Feeds

Electron transport in electrospun TiO2 nanofiber dye-sensitized solar cells

Kunal Mukherjee, Tai-Hou Teng, Rajan Jose, and Seeram Ramakrishna

Appl. Phys. Lett. 95, 012101 (2009); http://dx.doi.org/10.1063/1.3167298 (3 pages) | Cited 33 times

Online Publication Date: 6 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this study dye-sensitized solar cells (DSCs) were fabricated using electrospun TiO2 nanofibers. Electrochemical impedance spectroscopy and open-circuit voltage decay were used to analyze electron transport in electrospun nanofibers and determine their applicability in DSCs. The polycrystalline nature and random web structure of the nanofibers exhibit effective electron diffusion coefficients close to that of high efficiency nanoparticle cells. The electron lifetime was, however, low due to the presence of a large number of surface traps despite the presence of a space-charge recombination barrier.
Show PACS
84.60.Jt Photoelectric conversion
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
73.63.Bd Nanocrystalline materials
66.30.Pa Diffusion in nanoscale solids
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
81.16.-c Methods of micro- and nanofabrication and processing

Phase change behavior in oxygen-incorporated Ge2Sb2Te5 films

M. H. Jang, S. J. Park, D. H. Lim, M.-H. Cho, K. H. Do, D.-H. Ko, and H. C. Sohn

Appl. Phys. Lett. 95, 012102 (2009); http://dx.doi.org/10.1063/1.3168551 (3 pages) | Cited 6 times

Online Publication Date: 6 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Oxygen-incorporated Ge2Sb2Te5 (GST) films were deposited using ion beam sputtering deposition. Sheet resistance in films with 16.7% oxygen content decreased at a higher annealing temperature than that of undoped GST films, while resistance in films with an oxygen content of over 21.7% decreased dramatically at lower temperatures. X-ray diffraction patterns showed crystallization to face-centered cubic phase was suppressed. However, phase separation to a hexagonal structure was observed in films with an oxygen content of over 21.7%. Extended x-ray absorption fine structure data of Ge K edge showed Ge was bonded to O as well as Te. Moreover, a stoichiometric GeO2 phase was not observed, while phase separation into Sb2O3 and Sb2Te3 occurred. The results indicate Ge–Te bonds with oxygen are related to structural stability.
Show PACS
68.55.ag Semiconductors
73.61.Le Other inorganic semiconductors
64.75.St Phase separation and segregation in thin films
64.75.Qr Phase separation and segregation in semiconductors
78.70.Dm X-ray absorption spectra
81.15.Cd Deposition by sputtering

Current conduction of 0.72 nm equivalent-oxide-thickness LaO/HfO2 stacked gate dielectrics

Chuan-Hsi Liu, Hung-Wen Chen, Shung-Yuan Chen, Heng-Sheng Huang, and Li-Wei Cheng

Appl. Phys. Lett. 95, 012103 (2009); http://dx.doi.org/10.1063/1.3170235 (3 pages) | Cited 7 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Metal-oxide-semiconductor capacitors (MOSCs) incorporating atomic layer deposited (ALD) LaO/HfO2 stacked gate dielectrics were fabricated, where the equivalent oxide thickness (EOT) of the high-k dielectrics is only 0.72 nm and the gate leakage (Jg) is as low as 6.8×10−2 A/cm2. Based on the analysis of the temperature dependence of the gate leakage current from 300 to 500 K, the main current conduction is found to be Schottky emission or Poole–Frankel emission. Moreover, the barrier height (ΦB) at TaC and HfLaO interface is estimated to be about 1.21 eV, and the trap energy level (Φt) is about 0.51 eV.
Show PACS
84.32.Tt Capacitors
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Charging effect and capacitance modulation of Ni-rich NiO thin film

R. Ang, T. P. Chen, Z. Liu, J. I. Wong, M. D. Yi, M. Yang, Z. H. Cen, S. Zhu, W. Zhu, and E. S. M. Goh

Appl. Phys. Lett. 95, 012104 (2009); http://dx.doi.org/10.1063/1.3170353 (3 pages) | Cited 3 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, Ni-rich NiO thin film is deposited on p-type Si substrate by dc magnetron sputtering to form a metal-insulator-semiconductor structure. The charge trapping in the Ni nanocrystals (nc-Ni) embedded in NiO matrix induces a flatband voltage shift and capacitance modulation, which could be used for memory applications. The charging of nc-Ni depends on the voltage polarity, as well as the charging time and magnitude of gate voltage. The capacitance modulation can be described by an equivalent circuit model.
Show PACS
73.63.-b Electronic transport in nanoscale materials and structures
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
81.15.Cd Deposition by sputtering
68.55.at Other materials
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Multiferroic oxides-based flash memory and spin-field-effect transistor

Chenglong Jia and Jamal Berakdar

Appl. Phys. Lett. 95, 012105 (2009); http://dx.doi.org/10.1063/1.3173203 (3 pages) | Cited 13 times

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose a modified spin-field-effect transistor fabricated in a two dimensional electron gas (2DEG) formed at the surface of multiferroic oxides with a transverse helical magnetic order. The topology of the oxide local magnetic moments induces a resonant momentum-dependent effective spin-orbit interaction acting on 2DEG. We show that spin polarization dephasing is strongly suppressed, which is crucial for functionality. The carrier spin precession phase depends linearly on the magnetic spiral helicity. The latter is electrically controllable by virtue of the magneto-electric effect. We also suggest a flash-memory device based on this structure.
Show PACS
85.30.Tv Field effect devices
84.30.Sk Pulse and digital circuits
85.50.Gk Non-volatile ferroelectric memories

A passivated codoping approach to tailor the band edges of TiO2 for efficient photocatalytic degradation of organic pollutants

Dan Wang, Yanhong Zou, Shuangchun Wen, and Dianyuan Fan

Appl. Phys. Lett. 95, 012106 (2009); http://dx.doi.org/10.1063/1.3174917 (3 pages) | Cited 10 times

Online Publication Date: 8 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose an effective passivated codoping approach to tailor the band edges of TiO2 by doping the host with group IVA and group VIB impurities to passive donor-acceptor complexes. A way of achieving p-type TiO2 is found, which can outspread the application range of TiO2 semiconductor. It is demonstrated that the carbon (C)/tungsten (W) codoped TiO2 has a substantial increase in the valence band edge, while leaving the conduction band edge almost unchanged, thus improving the efficiency of photocatalytic degradation of organic pollutants. In principle, the suggested approach for overcoming the p-type doping bottleneck can be applied to other wide-band-gap semiconductors.
Show PACS
71.20.Nr Semiconductor compounds
61.72.up Other materials
82.50.-m Photochemistry
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Abnormal magnetic-field dependence of Hall coefficient in InN epilayers

T. A. Komissarova, M. A. Shakhov, V. N. Jmerik, T. V. Shubina, R. V. Parfeniev, S. V. Ivanov, X. Wang, and A. Yoshikawa

Appl. Phys. Lett. 95, 012107 (2009); http://dx.doi.org/10.1063/1.3167823 (3 pages) | Cited 5 times

Online Publication Date: 9 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on magnetic-field dependences of Hall coefficient and resistivity for InN films grown by plasma-assisted molecular beam epitaxy. The Hall coefficient rises with the magnetic field. This anomalous behavior is discussed in terms of the presence of highly conducting inhomogeneities in the films. According to the magnetic field and temperature dependences of the film resistivity, the inhomogeneities are attributed to metallic indium nanoparticles formed presumably around extended defects within the InN epilayers, at their surface and the InN/GaN interface. Good correlation is observed between the growth conditions of the InN films and their electrical properties recalculated using the model.
Show PACS
73.61.Ey III-V semiconductors
68.55.ag Semiconductors
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
72.20.My Galvanomagnetic and other magnetotransport effects
71.55.Eq III-V semiconductors
61.72.Nn Stacking faults and other planar or extended defects

Solution-processed InGaZnO-based thin film transistors for printed electronics applications

Jun Hyung Lim, Jong Hyun Shim, Jun Hyuk Choi, Jinho Joo, Kyung Park, Haseok Jeon, Mi Ran Moon, Donggeun Jung, Hyoungsub Kim, and Hoo-Jeong Lee

Appl. Phys. Lett. 95, 012108 (2009); http://dx.doi.org/10.1063/1.3157265 (3 pages) | Cited 26 times

Online Publication Date: 9 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter reports the utility of using the sol-gel process for exploring the library of multicomponent ZnO-based oxides as an active layer of thin film transistors. We chose InGaZnO as a starting material and modulated the Ga content to examine the potential of this material. Increasing the Ga ratio from 0.1 to 1 brought about a dynamic shift in the electrical behavior from conductor to semiconductor. This exploratory work critically helped us fabricate a device with robust device performance (a mobility of 1 ∼ 2 cm2 V−1 s−1 for the 400 °C-sintered samples and 0.2 cm2 V−1 s−1 for the 300 °C-sintered samples).
Show PACS
85.30.Tv Field effect devices
81.05.Dz II-VI semiconductors

Resistance switching in a single-crystalline NiO thin film grown on a Pt0.8Ir0.2 electrode

Masanori Kawai, Kimihiko Ito, and Yuichi Shimakawa

Appl. Phys. Lett. 95, 012109 (2009); http://dx.doi.org/10.1063/1.3179169 (3 pages) | Cited 8 times

Online Publication Date: 10 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A single-crystalline NiO thin film was grown epitaxially on an atomically flat Pt0.8Ir0.2 bottom electrode layer grown epitaxially on a SrTiO3(100) substrate. The memory cells of the single-crystalline NiO thin film with Pt top electrodes showed unipolar resistance switching behaviors. The result demonstrates that a unipolar resistance switching is not a characteristic phenomenon in the polycrystalline NiO but it can also occur in the single-crystalline NiO.
Show PACS
73.61.-r Electrical properties of specific thin films
68.55.A- Nucleation and growth

Inhomogeneous chemical states in resistance-switching devices with a planar-type Pt/CuO/Pt structure

R. Yasuhara, K. Fujiwara, K. Horiba, H. Kumigashira, M. Kotsugi, M. Oshima, and H. Takagi

Appl. Phys. Lett. 95, 012110 (2009); http://dx.doi.org/10.1063/1.3175720 (3 pages) | Cited 21 times

Online Publication Date: 10 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The spatial distribution of chemical states in resistance-switching devices with a planar-type Pt/CuO/Pt structure has been studied by photoemission electron microscopy. It has been found that the change in resistance that occurs with the application of the first voltage is caused by the formation of a reduction path through the CuO channel between the Pt electrodes. A detailed analysis suggests that Joule-heat-assisted reduction induced by the current flowing through the device may play an important role in the formation of the conductive reduction path.
Show PACS
84.30.Sk Pulse and digital circuits
79.60.Jv Interfaces; heterostructures; nanostructures
73.40.Sx Metal-semiconductor-metal structures

Interfacial structure of InAs/Ga1−xInxSb superlattices

Maohua Quan, Lihua Wang, Ke Wang, Fengyun Guo, Xiaodong Han, and Liancheng Zhao

Appl. Phys. Lett. 95, 012111 (2009); http://dx.doi.org/10.1063/1.3175722 (3 pages) | Cited 2 times

Online Publication Date: 10 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The interfacial structure of InAs/Ga1−xInxSb superlattices is investigated by high-resolution transmission electron microscopy imaging. We have shown that high-resolution electron microscopy with quantitative image matching can enable the relative orientation of the closely separated atomic species in InAs and Ga1−xInxSb to be resolved. We have then used this capability to determine interfacial bonds. The shift in the atomic positions associated with this modulation may lead to distortions of the interfacial structure of Ga1−xInxAs-like. The misfit dislocations in InSb-like interface are the primary mechanism for accommodating the lattice mismatch.
Show PACS
73.21.Cd Superlattices
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.37.Lp Transmission electron microscopy (TEM)
71.20.Nr Semiconductor compounds

Observation of hole accumulation at the interface of an undoped InGaN/GaN heterostructure

D. J. Chen, J. J. Xue, B. Liu, H. Lu, Z. L. Xie, P. Han, R. Zhang, Y. D. Zheng, Y. C. Kong, and J. J. Zhou

Appl. Phys. Lett. 95, 012112 (2009); http://dx.doi.org/10.1063/1.3176443 (3 pages) | Cited 2 times

Online Publication Date: 10 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A pronounced hump structure at about −5 V in the high-frequency capacitance-voltage (C-V) curve of an undoped InGaN/GaN heterostructure is observed and this hump weakens gradually with decreasing measurement frequency, indicating the occurrence of an inversion behavior in the InGaN/GaN heterostructure. The inversion behavior in the C-V curve is attributed to hole accumulation at the heterointerface where a hole well is formed due to the strong piezoelectric polarization effect in the InGaN/GaN heterostructure. The acceptor traps related to Ga vacancies in the InGaN layer are thought to be the source of the minority carriers. The theoretical calculation of band diagram of the InGaN/GaN heterostructure confirms the formation of the hole well at the heterointerface and supports the behavior of hole accumulation under negative bias voltage.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Ey III-V semiconductors
81.05.Ea III-V semiconductors
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
73.50.Mx High-frequency effects; plasma effects
61.72.jd Vacancies
77.65.-j Piezoelectricity and electromechanical effects

Dimensional crossover and weak localization in a 90 nm n-GaAs thin film

A. M. Gilbertson, A. K. M. Newaz, Woo-Jin Chang, R. Bashir, S. A. Solin, and L. F. Cohen

Appl. Phys. Lett. 95, 012113 (2009); http://dx.doi.org/10.1063/1.3176968 (3 pages) | Cited 1 time

Online Publication Date: 10 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the magnetotransport in a 90 nm thick n-type GaAs epitaxial thin film in the weak localization (WL) regime. Low temperature (T ≤ 50 K) magnetotransport data are fit with WL theory, from which the phase coherence time, τϕ∝T−p (p = 1.22±0.01), are extracted. We conclude that the dominant dephasing mechanism at these temperatures is electron-electron (e-e) scattering in the Nyquist limit. Evidence of a crossover from two-dimensional to three-dimensional behavior with respect to both coherent transport (WL) and e-e interactions is observed in the temperature dependence of the zero-field conductivity and τϕ, respectively.
Show PACS
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
73.61.Ey III-V semiconductors
back to top
RSS Feeds

Search for transformation from paramagnetic martensite to ferromagnetic austenite: NiMnGaCu alloys

Chengbao Jiang, Jingmin Wang, Panpan Li, Ao Jia, and Huibin Xu

Appl. Phys. Lett. 95, 012501 (2009); http://dx.doi.org/10.1063/1.3155199 (3 pages) | Cited 9 times

Online Publication Date: 6 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Search for transformation from paramagnetic martensite to ferromagnetic austenite in ferromagnetic shape memory alloys is performed through designing NiMnGaCu alloys. The composition dependence of the martensitic transformation temperature TM, the magnetic transition temperatures TCA of the austenite and TCM of the martensite is systematically investigated. The sequence of the martensitic transformation and magnetic transition is determined. The diagram on the structural and magnetic transition in a specific system Ni46Mn25+xGa25−xCu4 is outlined, in which a transformation from paramagnetic martensite to ferromagnetic austenite is predicted, exhibiting TCM<TM<TCA. Such a transformation is then experimentally achieved in Ni46Mn33Ga17Cu4 alloy.
Show PACS
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Cc Other ferromagnetic metals and alloys
81.30.Kf Martensitic transformations
64.70.kd Metals and alloys

Double magnetic tunnel junctions with cross-magnetization configurations for electrical detection of domain-wall structures

Tetsuya Uemura (植村哲也), Keisuke Sawada (澤田圭佑), Ken-ichi Matsuda (松田健一), and Masafumi Yamamoto (山本眞史)

Appl. Phys. Lett. 95, 012502 (2009); http://dx.doi.org/10.1063/1.3168514 (3 pages) | Cited 1 time

Online Publication Date: 7 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A device consisting of double magnetic tunnel junctions with cross-magnetization configurations is proposed to enable simultaneous electrical detection of both the structure and motion of a domain-wall (DW). Operation of this device has been confirmed through micromagnetic simulation. Owing to the cross-magnetization configurations, two types of DW structure formed in a ferromagnetic wire were clearly identified: a transverse wall (TW) in which the magnetization at the center of the wall is directed transversely to the wire axis and a vortex wall (VW) in which the magnetization circulates in the plane around a small perpendicular vortex core. In addition to the structural difference between TW and VW, the velocity of the DW motion was detected through the time response of the tunneling magnetoresistance.
Show PACS
75.47.Pq Other materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Ch Domain walls and domain structure

Locally induced domain wall damping in a thin magnetic wire

G. Infante, R. Varga, G. A. Badini-Confalonieri, and M. Vázquez

Appl. Phys. Lett. 95, 012503 (2009); http://dx.doi.org/10.1063/1.3174919 (3 pages) | Cited 5 times

Online Publication Date: 8 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The damping mechanisms affecting the motion of a single domain wall were studied in a thin bistable magnetic wire. It was found that the overall damping is frequency and temperature dependent through the locally induced anisotropy via structural relaxation. This phenomenon can increase the overall damping by one order of magnitude and enables an effective tailoring of the domain wall dynamics according to required application.
Show PACS
75.60.Ch Domain walls and domain structure
75.30.Gw Magnetic anisotropy

Observation of microwave-assisted magnetization reversal in Fe65Co35 thin films through ferromagnetic resonance measurements

Corneliu Nistor, Ke Sun, Zihui Wang, Mingzhong Wu, Christoph Mathieu, and Matthew Hadley

Appl. Phys. Lett. 95, 012504 (2009); http://dx.doi.org/10.1063/1.3175721 (3 pages) | Cited 12 times

Online Publication Date: 8 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter reports a new approach for microwave-assisted magnetization reversal (MAMR) measurements and the demonstration of MAMR in a Fe65Co35 thin film with this approach. The approach uses a microstrip line to deliver microwaves to and measure the ferromagnetic resonance (FMR) of the sample. The switching field is determined through the measurements of the FMR absorption as a function of static field. In the presence of microwaves, a reduction in switching field by 50% was observed in a Fe65Co35 film. This reduction was independent of the duration of microwave pulses. This indicates the reduction is not a heating effect.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Bb Fe and its alloys

Magnetotransport properties of p-type carbon-doped ZnO thin films

T. S. Herng, S. P. Lau, L. Wang, B. C. Zhao, S. F. Yu, M. Tanemura, A. Akaike, and K. S. Teng

Appl. Phys. Lett. 95, 012505 (2009); http://dx.doi.org/10.1063/1.3176434 (3 pages) | Cited 34 times

Online Publication Date: 8 July 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Carbon-doped ZnO (ZnO:C) thin films exhibiting Curie temperature above room temperature were fabricated using ion beam technique. The magnetic moment of the ZnO:C films was found to be around 1.35 μB per carbon atom. The ZnO:C films showed p-type conduction with a hole concentration of ∼ 5×1017 cm−3. In addition, the anomalous Hall effect and negative magnetoresistance can be detected in the ZnO:C films. The magnetotransport properties of the ZnO:C suggested that the films possessed charge carrier spin polarization.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Pp Magnetic semiconductors
72.25.Dc Spin polarized transport in semiconductors
73.61.Ga II-VI semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
Page 2 of 5 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close