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

18 Apr 2011

Volume 98, Issue 16, Articles (16xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 98, 163701 (2011); http://dx.doi.org/10.1063/1.3579156 (3 pages)

Thomas Jetzfellner, Amir Rosenthal, K.-H. Englmeier, Alexander Dima, Miguel Ángel Araque Caballero, Daniel Razansky, and Vasilis Ntziachristos
Enlarge Image | Read More
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Selective growth of perovskite oxides on SrTiO3 (001) by control of surface reconstructions

Soo-hyon Phark, Young Jun Chang, and Tae Won Noh

Appl. Phys. Lett. 98, 161908 (2011); http://dx.doi.org/10.1063/1.3583443 (3 pages) | Cited 3 times

Online Publication Date: 21 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report surface reconstruction (RC)-dependent growths of SrTiO3 and SrVO3 on a SrTiO3 (001) surface with two different coexisting surface RCs, namely, (2×1) and c(6×2). Up to the coverage of several layers, epitaxial growth was forbidden on the c(6×2) RC under the growth conditions that permitted layer-by-layer epitaxial growth on the (2×1) RC. Scanning tunneling microscopy on the lattice structure of the c(6×2) RC revealed that this RC-selective growth mainly originated from the significant structural/stoichiometric dissimilarity between the c(6×2) RC and the cubic perovskite films. On the c(6×2) RC, therefore, formation of perovskite islands was forbidden from the nucleation stage.
Show PACS
68.55.aj Insulators
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.66.Bi Elemental solids
61.66.Dk Alloys

Orientation dependence of the elastic instability on strained SiGe films

J.-N. Aqua, A. Gouyé, T. Auphan, T. Frisch, A. Ronda, and I. Berbezier

Appl. Phys. Lett. 98, 161909 (2011); http://dx.doi.org/10.1063/1.3576916 (3 pages) | Cited 2 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
At low strain, SiGe films on Si substrates undergo the Asaro–Tiller–Grinfeld morphological instability. We demonstrate experimentally that this instability develops on Si(001) but not on Si(111) even after long annealing. Using a continuum description of surface diffusion in presence of wetting, elasticity, and surface energy anisotropy, we find a retardation of the instability on Si(111) due to a strong dependence of the instability onset as function of the surface stiffness. This retardation is at the origin of the inhibition of the instability on experimental time scales even after long annealing.
Show PACS
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
81.40.Gh Other heat and thermomechanical treatments
65.40.gp Surface energy

An analytical model for the growth of quantum dots on ultrathin substrates

S. P. A. Gill

Appl. Phys. Lett. 98, 161910 (2011); http://dx.doi.org/10.1063/1.3583447 (3 pages) | Cited 1 time

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The self-assembly of heteroepitaxial quantum dots on ultrathin substrates is analyzed within the context of small perturbation theory. Analytical expressions are derived for the dependence of the quantum dot separation on the substrate thickness. It is shown that the substrate thickness is critical in determining this separation when it is below the intrinsic material length scale of the system. The model is extended to simultaneous dot growth on both sides of the substrate. It is shown that vertically anticorrelated structures are preferred with an increase in the dot separation of 15% above that found in the one-sided case.
Show PACS
81.07.Ta Quantum dots
81.15.Aa Theory and models of film growth

Electroabsorption spectra of PbSe nanocrystal quantum dots

Xiaoming Liu, Toshifumi Iimori, Ruriko Ohshima, Takakazu Nakabayashi, and Nobuhiro Ohta

Appl. Phys. Lett. 98, 161911 (2011); http://dx.doi.org/10.1063/1.3583450 (3 pages) | Cited 1 time

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The quantum-confined Stark effect of PbSe nanocrystal quantum dots (QDs) in a polymer film has been studied for the near-infrared absorption in the region of 1300–1600 nm (corresponding to diameters of 4.0–7.0 nm) by using electric field modulation spectroscopy. Electroabsorption spectra of QDs show the electric-field-induced energy shift in the exciton state, resulting in the spectral broadening given by the second derivative of the absorption spectra. It is shown that the magnitude of the change in electric dipole moment following excitation into the first exciton state increases with an increase in the size of QDs.
Show PACS
78.20.Jq Electro-optical effects
78.30.Hv Other nonmetallic inorganics
78.67.Hc Quantum dots
71.35.-y Excitons and related phenomena
73.21.La Quantum dots

Optical anisotropy and photoluminescence polarization in single InAlAs quantum dots

S. Ohno, S. Adachi, R. Kaji, S. Muto, and H. Sasakura

Appl. Phys. Lett. 98, 161912 (2011); http://dx.doi.org/10.1063/1.3583453 (3 pages) | Cited 3 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the optical anisotropy in individual self-assembled quantum dots. The linear polarization analysis of the positive trion photoluminescence reveals the effect of the strain-induced valence band mixing since the positive trion has the spin-paired holes and therefore exchange interaction has no influence. Meanwhile, the neutral exciton indicates the complex polarization states due to both the in-plain asymmetries of the dot shape and the strain distributions. The experimental and theoretical polarization analysis has been performed for tens of InAlAs quantum dots and the correlation between the important parameters was investigated.
Show PACS
78.55.Cr III-V semiconductors
81.05.Ea III-V semiconductors
78.67.Hc Quantum dots
81.07.Ta Quantum dots

Effect of dislocation density on thermal boundary conductance across GaSb/GaAs interfaces

Patrick E. Hopkins, John C. Duda, Stephen P. Clark, Christopher P. Hains, Thomas J. Rotter, Leslie M. Phinney, and Ganesh Balakrishnan

Appl. Phys. Lett. 98, 161913 (2011); http://dx.doi.org/10.1063/1.3581041 (3 pages) | Cited 8 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the thermal boundary conductance across structurally-variant GaSb/GaAs interfaces characterized by different dislocations densities, as well as variably-rough Al/GaSb interfaces. The GaSb/GaAs structures are epitaxially grown using both interfacial misfit (IMF) and non-IMF techniques. We measure the thermal boundary conductance from 100 to 450 K with time-domain thermoreflectance. The thermal boundary conductance across the GaSb/GaAs interfaces decreases with increasing strain dislocation density. We develop a model for interfacial transport at structurally-variant interfaces in which phonon propagation and scattering parallels photon attenuation. We find that this model describes the measured thermal boundary conductances well.
Show PACS
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
66.70.Df Metals, alloys, and semiconductors
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.ag Semiconductors
back to top
RSS Feeds

Spin and momentum filtering of electrons on the surface of a topological insulator

Zhenhua Wu, F. M. Peeters, and Kai Chang

Appl. Phys. Lett. 98, 162101 (2011); http://dx.doi.org/10.1063/1.3581887 (3 pages) | Cited 3 times

Online Publication Date: 18 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate theoretically the transport properties of Dirac fermions on the surface of a three-dimensional topological insulator. Dirac electrons can be totally reflected in front of a magnetic/electric p-n junction. For a p-n-p structure, multiple total internal reflections at the interfaces result in the bound states in the channel, which behaves like an electronic waveguide. This p-n-p like structure exhibits spin and momentum filtering features and could be used as a spin and/or charge diode.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.25.+i Surface conductivity and carrier phenomena
05.30.Fk Fermion systems and electron gas

Low-voltage gallium–indium–zinc–oxide thin film transistors based logic circuits on thin plastic foil: Building blocks for radio frequency identification application

A. K. Tripathi, E. C. P Smits, J. B. P. H. van der Putten, M. van Neer, K. Myny, M. Nag, S. Steudel, P. Vicca, K. O’Neill, E. van Veenendaal, J. Genoe, P. Heremans, and G. H. Gelinck

Appl. Phys. Lett. 98, 162102 (2011); http://dx.doi.org/10.1063/1.3579529 (3 pages) | Cited 6 times

Online Publication Date: 19 April 2011

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
In this work a technology to fabricate low-voltage amorphous gallium–indium–zinc oxide thin film transistors (TFTs) based integrated circuits on 25 μm foils is presented. High performance TFTs were fabricated at low processing temperatures (<150 °C) with field effect mobility around 17 cm2/V s. The technology is demonstrated with circuit building blocks relevant for radio frequency identification applications such as high-frequency functional code generators and efficient rectifiers. The integration level is about 300 transistors.
Show PACS
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
84.30.Sk Pulse and digital circuits

Iron distribution in silicon after solar cell processing: Synchrotron analysis and predictive modeling

D. P. Fenning, J. Hofstetter, M. I. Bertoni, S. Hudelson, M. Rinio, J. F. Lelièvre, B. Lai, C. del Cañizo, and T. Buonassisi

Appl. Phys. Lett. 98, 162103 (2011); http://dx.doi.org/10.1063/1.3575583 (3 pages) | Cited 6 times

Online Publication Date: 20 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The evolution during silicon solar cell processing of performance-limiting iron impurities is investigated with synchrotron-based x-ray fluorescence microscopy. We find that during industrial phosphorus diffusion, bulk precipitate dissolution is incomplete in wafers with high metal content, specifically ingot border material. Postdiffusion low-temperature annealing is not found to alter appreciably the size or spatial distribution of FeSi2 precipitates, although cell efficiency improves due to a decrease in iron interstitial concentration. Gettering simulations successfully model experiment results and suggest the efficacy of high- and low-temperature processing to reduce both precipitated and interstitial iron concentrations, respectively.
Show PACS
88.40.jj Silicon solar cells
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods
61.72.Cc Kinetics of defect formation and annealing

Lifetime recovery in p-type Czochralski silicon due to the reconfiguration of boron–oxygen complexes via a hole-emitting process

Bianca Lim, Vladimir V. Voronkov, Robert Falster, Karsten Bothe, and Jan Schmidt

Appl. Phys. Lett. 98, 162104 (2011); http://dx.doi.org/10.1063/1.3581215 (3 pages) | Cited 3 times

Online Publication Date: 20 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The recovery of the light-degraded lifetime during annealing in darkness at 120 to 160 °C is examined in boron-doped p-type Czochralski silicon (Cz-Si) as well as in compensated Cz-Si codoped with boron and phosphorus. The rate constant for the recovery is found to be inversely proportional to the hole concentration for both boron-doped and compensated material. Our experiments confirm a model, in which the process of recovery is assigned to a reconfiguration of a boron–oxygen defect complex, whereby a hole is emitted. The activation energy for the recovery process is determined to be (1.36±0.06) eV.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
61.72.jj Interstitials
72.80.Cw Elemental semiconductors
81.05.Cy Elemental semiconductors
61.72.uf Ge and Si
81.10.Fq Growth from melts; zone melting and refining

Minority carrier transport length of electrodeposited Cu2O in ZnO/Cu2O heterojunction solar cells

Yingchi Liu, Hubert K. Turley, John R. Tumbleston, Edward T. Samulski, and Rene Lopez

Appl. Phys. Lett. 98, 162105 (2011); http://dx.doi.org/10.1063/1.3579259 (3 pages) | Cited 12 times

Online Publication Date: 21 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The minority carrier transport length is a critical parameter limiting the performance of inexpensive Cu2O–ZnO photovoltaic devices. In this letter, this length is estimated to be ∼ 430 nm for electrochemically deposited Cu2O by linking the cell’s carrier generation profile with back and front incident photon-to-electron conversion efficiency measurements to a one-dimensional transport model. This critical length explains the losses typically presented by these devices and appears to correlate well with the microcrystalline film structure. The consequences of the magnitude of the length on device design with the aim of improving solar cell performance are described.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
88.40.H- Solar cells (photovoltaics)
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.05.Dz II-VI semiconductors

Promising thermoelectric properties in AgxMo9Se11 compounds (3.4 ≤ x ≤ 3.9)

Tong Zhou, Bertrand Lenoir, Malika Colin, Anne Dauscher, Rabih Al Rahal Al Orabi, Patrick Gougeon, Michel Potel, and Emmanuel Guilmeau

Appl. Phys. Lett. 98, 162106 (2011); http://dx.doi.org/10.1063/1.3579261 (3 pages) | Cited 4 times

Online Publication Date: 21 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polycrystalline Mo9 cluster chalcogenides AgxMo9Se11 (3.4 ≤ x ≤ 3.9) have been prepared by powder metallurgy techniques, sintered by spark plasma sintering and characterized by x-ray diffraction. Their thermoelectric properties (electrical resistivity, thermopower, thermal conductivity) have been determined in the 300–800 K temperature range. The AgxMo9Se11 compounds show p-type conduction characteristics. The outstanding low lattice thermal conductivities give rise to a rather high value of the dimensionless thermoelectric figure of merit ZT of ∼ 0.65 at 800 K for x = 3.8–3.9, making this family of materials particularly promising for thermoelectric power generation applications.
Show PACS
72.20.Pa Thermoelectric and thermomagnetic effects
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves

The effect of electronegative difference on the electronic structure and visible light photocatalytic activity of N-doped anatase TiO2 by first-principles calculations

Dongqiu Zhao, Xiaowei Huang, Baoli Tian, Shaomin Zhou, Yuncai Li, and Zuliang Du

Appl. Phys. Lett. 98, 162107 (2011); http://dx.doi.org/10.1063/1.3579199 (3 pages) | Cited 10 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of electronegative difference between nitrogen and oxygen on electronic properties of N-doped anatase TiO2 has been studied using first-principles calculations. The results indicate that the valence band maximum (VBM) shifts to high energy by 0.27 eV and the band gap states composed of N 2p, O 2p, and Ti 3d states are formed through the three states entering into the gap after N doping. The interactions of three states widen and delocalize the band gap states. The raised VBM and the wide band gap states can improve the visible light photocatalytic activity.
Show PACS
71.20.Nr Semiconductor compounds
71.15.-m Methods of electronic structure calculations
61.72.up Other materials
82.50.Hp Processes caused by visible and UV light
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

High-performance gate-all-around polycrystalline silicon nanowire with silicon nanocrystals nonvolatile memory

Min-Feng Hung, Yung-Chun Wu, and Zih-Yun Tang

Appl. Phys. Lett. 98, 162108 (2011); http://dx.doi.org/10.1063/1.3582925 (3 pages) | Cited 4 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nonvolatile memory (NVM) that is based on gate-all-around (GAA) and polycrystalline silicon (poly-Si) nanowires structure with silicon nanocrystals (NCs) as the storage nodes is demonstrated. The GAA poly-Si–SiO2–Si3N4–SiO2–poly-Si (SONOS) NVMs are also fabricated and compared. The GAA NCs NVMs have a 4.2 V of threshold voltage shift at 18 V for 1 ms, and are faster than the GAA SONOS NVMs do. In reliability studies, this NVM shows superior endurance after 104 program/erase (P/E) cycles, and loses only 14% of its charges lose after ten years at 85 °C.
Show PACS
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
84.30.Sk Pulse and digital circuits

Cyclotron resonance mass and Fermi energy pinning in the In(AsN) alloy

O. Drachenko, A. Patanè, N. V. Kozlova, Q. D. Zhuang, A. Krier, L. Eaves, and M. Helm

Appl. Phys. Lett. 98, 162109 (2011); http://dx.doi.org/10.1063/1.3583378 (3 pages) | Cited 3 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report cyclotron resonance (CR) experiments on the midinfrared alloy InAs1−xNx grown on GaAs with x from 0% to 1.9%. Using magnetic fields up to 60 T and terahertz photon sources from 3 to 30 THz, we determine the dependence on x of the electron density and CR mass. The increase in the carrier density with increasing x is accompanied by a redshift in the interband photoluminescence emission and is explained in terms of the pinning of the Fermi level to its value at x = 0. The high carrier densities ( ∼ 1018 cm−3) at x ∼ 1% give rise to a CR mass that is only weakly dependent on the excitation energy, significantly weaker than that in InAs.
Show PACS
73.61.Ey III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
71.20.-b Electron density of states and band structure of crystalline solids
72.20.-i Conductivity phenomena in semiconductors and insulators

Influence of growth temperature on AlGaN multiquantum well point defect incorporation and photoluminescence efficiency

A. Armstrong, A. A. Allerman, T. A. Henry, and M. H. Crawford

Appl. Phys. Lett. 98, 162110 (2011); http://dx.doi.org/10.1063/1.3583448 (3 pages) | Cited 3 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dependence of (Al)GaN/AlGaN multiquantum well (MQWs) optical efficiency and defect incorporation on the growth temperature (Tg) of the optically active region was investigated. Marked increase in MQW photoluminescence (PL) intensity was observed for increasing Tg. Correspondingly, increasing Tg also significantly reduced point defect incorporation under QW growth conditions, as determined by deep level optical spectroscopy. It is suggested that enhanced MQW PL with increasing Tg resulted from improved nonradiative lifetime through reduced nonradiative defect density in the MQW region.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.65.Fg Quantum wells
68.55.ag Semiconductors
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors

Schottky barrier height on thermally oxidized InAlN surface evaluated by electrical and optical measurements

J. Kováč, R. Šramatý, A. Chvála, H. Sibboni, E. Morvan, M. A. DiForte-Poisson, D. Donoval, and P. Kordoš

Appl. Phys. Lett. 98, 162111 (2011); http://dx.doi.org/10.1063/1.3583458 (3 pages) | Cited 4 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Current transport and Schottky barrier height analysis on InAlN/GaN structures with thermally oxidized InAlN surface (800 °C, 1 min) was performed. From the current-voltage characteristics measured at various temperatures (300–820 K) and their approximation by various current mechanisms, it follows that the tunneling current dominates. Extraction of the thermionic emission yielded the Schottky barrier height of 2.43 eV at 300 K and its slight decrease with increased temperature. Optical method (photoemission current vs photon energy) allows direct barrier height evaluation without analyzing current mechanisms. Comparative analysis using optical method yielded the room-temperature barrier height of 2.57 eV. Obtained barrier heights document significant barrier enhancement due an InAlN oxidation. This result confirms the thermal oxidation procedure as a useful tool at the preparation of reliable InAlN-based devices.
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
81.65.Mq Oxidation
79.40.+z Thermionic emission
79.60.Jv Interfaces; heterostructures; nanostructures

AlGaN/GaN high-electron mobility transistors with low thermal resistance grown on single-crystal diamond (111) substrates by metalorganic vapor-phase epitaxy

Kazuyuki Hirama, Yoshitaka Taniyasu, and Makoto Kasu

Appl. Phys. Lett. 98, 162112 (2011); http://dx.doi.org/10.1063/1.3574531 (3 pages) | Cited 4 times

Online Publication Date: 22 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
AlGaN/GaN heterostructures with a wurtzite structure were epitaxially grown on single-crystal diamond (111) with a diamond structure by metalorganic vapor phase epitaxy. In the AlGaN/GaN heterostructure, two-dimensional electron gas with sheet carrier density of 1.0×1013 cm−2 and mobility of 730 cm2/V s was obtained. The 3-μm-gate-length AlGaN/GaN high-electron mobility transistors (HEMTs) show maximum drain current of 220 mA/mm, cut-off frequency of 3 GHz, and maximum frequency of oscillation of 7 GHz. The thermal resistance of the AlGaN/GaN HEMTs on diamond substrates is 4.1 K mm/W, the lowest ever reported for AlGaN/GaN HEMTs, due to the high thermal conductivity of single-crystal diamond.
Show PACS
85.30.Tv Field effect devices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
back to top
RSS Feeds

Fine tuning of phase qubit parameters for optimization of fast single-pulse readout

Leonid S. Revin and Andrey L. Pankratov

Appl. Phys. Lett. 98, 162501 (2011); http://dx.doi.org/10.1063/1.3582615 (3 pages)

Online Publication Date: 18 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We analyze a two-level quantum system, describing the phase qubit, during a single-pulse readout process by a numerical solution of the time-dependent Schroedinger equation. It has been demonstrated that the readout error has a minimum for certain values of the system’s basic parameters. In particular, the optimization of the qubit capacitance and the readout pulse shape leads to significant reduction in the readout error. It is shown that in an ideal case the fidelity can be increased to almost 97% for 2 ns pulse duration and to 96% for 1 ns pulse duration.
Show PACS
03.67.Lx Quantum computation architectures and implementations
03.65.Ge Solutions of wave equations: bound states

Spin-torque switching window, thermal stability, and material parameters of MgO tunnel junctions

T. Devolder, L. Bianchini, K. Miura, K. Ito, Joo-Von Kim, P. Crozat, V. Morin, A. Helmer, C. Chappert, S. Ikeda, and H. Ohno

Appl. Phys. Lett. 98, 162502 (2011); http://dx.doi.org/10.1063/1.3576937 (3 pages) | Cited 4 times

Online Publication Date: 18 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the use of in-plane magnetized free layers with artificially lowered effective magnetization, in the context of spin-torque random access memories with magnetic tunnel junctions. We determine the field-voltage window for direct overwrite switching and thermal stability. We relate them to the magnetic constants extracted from the telegraph noise and high frequency noise exhibited by the junctions under specific conditions.
Show PACS
85.75.Dd Magnetic memory using magnetic tunnel junctions

Bound magnetic polarons and p-d exchange interaction in ferromagnetic insulating Cu-doped ZnO

Yufeng Tian, Yongfeng Li, Mi He, Irwan Ade Putra, Haiyang Peng, Bin Yao, Siew Ann Cheong, and Tom Wu

Appl. Phys. Lett. 98, 162503 (2011); http://dx.doi.org/10.1063/1.3579544 (3 pages) | Cited 26 times

Online Publication Date: 18 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A systematic study on the magnetic and electrical transport properties of single-phase wurtzite Zn1−xCuxO is performed. Efros variable range hopping dominates the conduction, which is accompanied by a ferromagnetic order up to 700 K for x>1%. Both the first-principles calculations and Cu/Al co-doping experiments suggest that the spontaneous spin polarization originates from the p-d exchange interaction between O 2p and Cu 3d orbitals. Furthermore, our results are consistent with the scenario that the intrinsic ferromagnetism is established through indirect interactions between bound magnetic polarons mediated by magnetic impurities.
Show PACS
75.30.Et Exchange and superexchange interactions
71.38.-k Polarons and electron-phonon interactions
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Pp Magnetic semiconductors
72.80.Ey III-V and II-VI semiconductors
72.25.-b Spin polarized transport
75.30.Hx Magnetic impurity interactions

Hall effect-induced acceleration of electromigration failures in spin valve multilayers under magnetic field

Jing Jiang, Ding Gui Zeng, Kyung-Won Chung, Jongryoul Kim, and Seongtae Bae

Appl. Phys. Lett. 98, 162504 (2011); http://dx.doi.org/10.1063/1.3581042 (3 pages)

Online Publication Date: 19 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It was observed that electromigration (EM)-induced failures in spin valve multilayers were severely accelerated by an externally applied magnetic field. The theoretical and experimental analysis results confirmed that Hall effect-induced Lorentz force applied to the perpendicular-to-the-film-plane direction is primarily responsible for the severe acceleration of the EM failures due to its dominant contribution to abruptly increasing local temperature and current density. The proposed failure model and the theoretical calculations were demonstrated to agree well with the experimental observations.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
66.30.Qa Electromigration

Improved tunneling magnetoresistance at low temperature in manganite junctions grown by molecular beam epitaxy

R. Werner, A. Yu. Petrov, L. Alvarez Miño, R. Kleiner, D. Koelle, and B. A. Davidson

Appl. Phys. Lett. 98, 162505 (2011); http://dx.doi.org/10.1063/1.3581885 (3 pages) | Cited 7 times

Online Publication Date: 20 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report resistance versus magnetic field measurements for a La0.65Sr0.35MnO3/SrTiO3/La0.65Sr0.35MnO3 tunnel junction grown by molecular-beam epitaxy, that show a large field window of extremely high tunneling magnetoresistance (TMR) at low temperature. Scanning the in-plane applied field orientation through 360°, the TMR shows fourfold symmetry, i.e., biaxial anisotropy, aligned with the crystalline axis but not the junction geometrical long axis. The TMR reaches ∼ 1900% at 4 K, corresponding to an interfacial spin polarization of >95% assuming identical interfaces. These results show that uniaxial anisotropy is not necessary for large TMR, and lay the groundwork for future improvements in TMR in manganite junctions.
Show PACS
75.47.Lx Magnetic oxides
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
75.30.Gw Magnetic anisotropy
72.25.-b Spin polarized transport
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Magnetic properties and phonon behavior of Pr2NiMnO6 thin films

M. P. Singh, K. D. Truong, S. Jandl, and P. Fournier

Appl. Phys. Lett. 98, 162506 (2011); http://dx.doi.org/10.1063/1.3575564 (3 pages) | Cited 1 time

Online Publication Date: 20 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the magnetic properties and the phonon behavior of epitaxial Pr2NiMnO6 (PNMO) films. The temperature dependence of their magnetic properties shows a ferromagnetic behavior up to 214 K owing to a dominant Ni2+/Mn4+ ordering. The observation of a secondary low-temperature magnetic transition around 126 K indicates that a small proportion of Ni/Mn disordered lattice remains in our films. Unlike La2NiMnO6, the temperature dependence of the 651 cm−1 Raman active phonon of our films reflects the presence of a weak spin–phonon coupling in PNMO.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
78.66.Nk Insulators
78.30.Hv Other nonmetallic inorganics
63.20.K- Phonon interactions

Structural controlled magnetic anisotropy in Heusler L10−MnGa epitaxial thin films

Kangkang Wang, Erdong Lu, Jacob W. Knepper, Fengyuan Yang, and Arthur R. Smith

Appl. Phys. Lett. 98, 162507 (2011); http://dx.doi.org/10.1063/1.3582244 (3 pages) | Cited 3 times

Online Publication Date: 20 April 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ferromagnetic L10−MnGa thin films have been epitaxially grown on GaN, sapphire, and MgO substrates using molecular beam epitaxy. Using diffraction techniques, the epitaxial relationships are determined. It is found that the crystalline orientation of the films differ due to the influence of the substrate. By comparing the magnetic anisotropy to the structural properties, a clear correlation could be established indicating that the in-plane and out-of-plane anisotropy is directly determined by the crystal orientation of the film and could be controlled via selection of the substrates. This result could be helpful in tailoring magnetic anisotropy in thin films for spintronic applications.
Show PACS
75.30.Gw Magnetic anisotropy
68.55.at Other materials
75.50.Cc Other ferromagnetic metals and alloys
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
75.70.Ak Magnetic properties of monolayers and thin films
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close