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

8 Dec 2008

Volume 93, Issue 23, Articles (23xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 93, 231101 (2008); http://dx.doi.org/10.1063/1.3040686 (3 pages)

Mads Brøkner Christiansen, Anders Kristensen, Sanshui Xiao, and Niels Asger Mortensen
Enlarge Image | Read More
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds
FREE

Real-time acoustic emission testing based on wavelet transform for the failure process of thermal barrier coatings

L. Yang, Y. C. Zhou, W. G. Mao, and C. Lu

Appl. Phys. Lett. 93, 231906 (2008); http://dx.doi.org/10.1063/1.3043458 (3 pages) | Cited 7 times

Online Publication Date: 10 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The fracture type differentiation, quantification, and source identification are desirable and yet intractable in the acoustic emission (AE) testing of a complex coating system. In this letter, a technique combining wavelet transform and conventional AE parameter analysis was developed to study the tensile failure process of thermal barrier coatings in real time. It is demonstrated that the failure of thermal barrier coatings originates from surface vertical cracking and follows interface cracking, and that the AE count increases with tensile load following a power law. The cracking source identified from AE signals agrees well with that observed by optical microscopy. This technique provides a powerful tool for the study of failure processes of a wide range of coatings and thin films.
Show PACS
68.60.Bs Mechanical and acoustical properties
81.70.Cv Nondestructive testing: ultrasonic testing, photoacoustic testing
81.40.Lm Deformation, plasticity, and creep
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.mm Fracture
62.20.mt Cracks
FREE

Uniform InGaAs quantum dot arrays fabricated using nanosphere lithography

X. Qian, J. Li, D. Wasserman, and W. D. Goodhue

Appl. Phys. Lett. 93, 231907 (2008); http://dx.doi.org/10.1063/1.3040683 (3 pages) | Cited 12 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the fabrication of optically active uniform InGaAs quantum dot arrays by combining nanosphere lithography and bromine ion-beam-assisted etching on a single InGaAs/GaAs quantum well. A wide range of lateral dot sizes was achieved from an oxygen plasma nanosphere resizing process. The increased lateral confinement of carriers in the dots results in low temperature photoluminescence blueshifts from 0.5 to 11 meV. Additional quantization was achieved using a selective wet-etch process. Our model suggests the presence of a 70 nm dead layer in the outer InGaAs radial edge, which we believe to be a result of defects and dislocations introduced during the dry-etch process.
Show PACS
81.16.Nd Micro- and nanolithography
78.67.De Quantum wells
78.67.Hc Quantum dots
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.65.Cf Surface cleaning, etching, patterning
81.15.Jj Ion and electron beam-assisted deposition; ion plating
FREE

Effects of disorder and scaling of optical conductivity in Nd0.5Ca0.5−xBaxMnO3 (x = 0 and 0.02) thin films as observed by terahertz time-domain spectroscopy

K. R. Mavani, M. Nagai, D. S. Rana, H. Yada, I. Kawayama, M. Tonouchi, and K. Tanaka

Appl. Phys. Lett. 93, 231908 (2008); http://dx.doi.org/10.1063/1.3041638 (3 pages) | Cited 5 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have explored the low energy charge dynamics of charge-ordered Nd0.5Ca0.5MnO3 and Ba-doped Nd0.5Ca0.48Ba0.02MnO3 manganite thin films by recording the complex optical spectra using terahertz time-domain spectroscopy. The extracted frequency- and temperature-dependent optical conductivity (σ) and dielectric constant (ε1) show distinct features at Néel’s ordering and the charge-ordering temperatures (TN and TCO). We found that the Ba-doping induced cation disorder effects on σ and ε1 are more pronounced above TCO, but these effects are subtle in a large temperature region below TCO. Both ε1 and σ increase as a function of temperature and form a scaling relationship ε1∝σ.
Show PACS
78.66.Nk Insulators
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
77.22.Ch Permittivity (dielectric function)
FREE

Bandgap engineering by tuning particle size and crystallinity of SnO2–Fe2O3 nanocrystalline composite thin films

M. B. Sahana, C. Sudakar, G. Setzler, A. Dixit, J. S. Thakur, G. Lawes, R. Naik, V. M. Naik, and P. P. Vaishnava

Appl. Phys. Lett. 93, 231909 (2008); http://dx.doi.org/10.1063/1.3042163 (3 pages) | Cited 15 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the structural and optical properties of xSnO2–yFe2O3 nanocrystalline composite thin films. SnO2 and Fe2O3 exhibit strong phase separation instability and their particle size and crystallinity are tunable by changing their composition and annealing temperature. The bandgap for these composites continuously increases from 2.3 to 3.89 eV. We discuss the increasing bandgap values in terms of the quantum confinement effect manifested by the decreasing size of Fe2O3 crystallites. The method provides a generic approach for the tuning of the bandgap in nanocomposite systems.
Show PACS
61.46.-w Structure of nanoscale materials
68.55.-a Thin film structure and morphology
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
73.22.-f Electronic structure of nanoscale materials and related systems
64.75.Jk Phase separation and segregation in nanoscale systems
FREE

Measurement and evaluation of the interfacial thermal resistance between a metal and a dielectric

Heng-Chieh Chien, Da-Jeng Yao, and Cheng-Ting Hsu

Appl. Phys. Lett. 93, 231910 (2008); http://dx.doi.org/10.1063/1.3039806 (3 pages) | Cited 6 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We used a sandwiched film structure of dielectric, metal, and dielectric to measure and also to estimate theoretically the metal-dielectric interfacial thermal resistance. In this structure, a metal layer with a thickness of about 10 nm, including chromium, titanium, aluminum, nickel, and platinum, is sandwiched between two SiO2 layers with a thickness of 100 nm prepared by plasma enhanced chemical vapor deposition. The estimates, 10−10–10−9 m2 K W−1, calculated with a continuum two-fluid model are significantly smaller than the measured values, ∼ 10−8 m2 K W−1. The continuum two-fluid model, according to the phenomena of electron-phonon nonequilibrium near the interface in a metal, cannot explain completely the cause of this metal-dielectric interfacial thermal resistance. From photographs of the transmission electron microscopy cross section, we argue that defects at an interface likely play an important role in the magnitude of the interfacial thermal resistance.
Show PACS
73.40.Ns Metal-nonmetal contacts
77.55.-g Dielectric thin films
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.jd Thickness
71.38.-k Polarons and electron-phonon interactions
63.20.kd Phonon-electron interactions
FREE

Residual strain in nonpolar a-plane Zn1−xMgxO (0<x<0.55) and its effect on the band structure of (Zn,Mg)O/ZnO quantum wells

J.-M. Chauveau, J. Vives, J. Zuniga-Perez, M. Laügt, M. Teisseire, C. Deparis, C. Morhain, and B. Vinter

Appl. Phys. Lett. 93, 231911 (2008); http://dx.doi.org/10.1063/1.3046783 (3 pages) | Cited 13 times

Online Publication Date: 12 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the dependence on Mg content of the lattice parameters and the surface morphology of nonpolar a-(11math0) Zn1−xMgxO (x ≤ 0.55) grown by molecular beam epitaxy. The anisotropy of the lattice parameters gives rise to an unusual in-plane strain state in the ZnO QWs: tensile strain along [1math00] and compressive strain along [0001]. For a Zn0.6Mg0.4O barrier, the strain in a ZnO QW reaches −1.3% along [0001] and +0.3% along [1math00]. This induces a strong blueshift of the excitonic transitions, in addition to the confinement effects, which we observe in photoluminescence excitation experiments.
Show PACS
73.21.Fg Quantum wells
68.35.bg Semiconductors
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
71.35.Lk Collective effects (Bose effects, phase space filling, and excitonic phase transitions)
78.55.Et II-VI semiconductors
78.67.De Quantum wells
FREE

Invariant critical stress for shear banding in a bulk metallic glass

Z. Han, H. Yang, W. F. Wu, and Y. Li

Appl. Phys. Lett. 93, 231912 (2008); http://dx.doi.org/10.1063/1.3048869 (3 pages) | Cited 6 times

Online Publication Date: 12 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Through uncovering the macroscopic true stress after correction with the instant load-bearing area, we found that the critical stress for continuous shear banding of a bulk metallic glass (BMG) maintains invariant on and after yielding as the plastic deformation progresses. This finding is in strong contrast with the previous reports of either “strain hardening” or “strain softening” associated with the plastic deformation of BMGs. Our results point out that atomic cohesive energy constantly serves to be the controlling factor of the critical stress for shear banding.
Show PACS
81.40.Lm Deformation, plasticity, and creep
62.20.fq Plasticity and superplasticity
back to top
RSS Feeds
FREE

Effects of artificially structured micrometer holes on the transport behavior of Al-doped ZnO layers

M. T. Elm, T. Henning, P. J. Klar, and B. Szyszka

Appl. Phys. Lett. 93, 232101 (2008); http://dx.doi.org/10.1063/1.3040312 (3 pages) | Cited 2 times

Online Publication Date: 9 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the transport properties of artificially structured n-type ZnO:Al thin films prepared by rf magnetron sputtering on glass substrates. The samples were patterned with an array of 4×4 and 8×8 μm2 holes. With decreasing hole size, the resistance of the samples increases. Filling the holes with Au or Al increases and decreases the resistance, respectively. All samples show a negative magnetoresistance, which becomes more pronounced with decreasing hole diameter. The filling of the holes with Au or Al reduces the effects of the artificial structuring on the magnetoresistance.
Show PACS
72.20.-i Conductivity phenomena in semiconductors and insulators
73.61.Ga II-VI semiconductors
85.40.Hp Lithography, masks and pattern transfer
FREE

Power dissipation spectra and terahertz intervalley transfer gain in bulk GaAs under high electric fields

Y. M. Zhu, T. Unuma, K. Shibata, K. Hirakawa, Y. Ino, and M. Kuwata-Gonokami

Appl. Phys. Lett. 93, 232102 (2008); http://dx.doi.org/10.1063/1.3039069 (3 pages) | Cited 6 times

Online Publication Date: 9 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated terahertz radiation emitted from electrons photoexcited by femtosecond laser pulses in bulk GaAs under strong bias electric fields. Power dissipation spectra of electrons for step-function-like input electric fields have been obtained by calculating Fourier spectra of the measured terahertz traces. The cutoff frequency νc for negative power dissipation (i.e., gain) due to intervalley transfer is found to gradually increase with increasing electric fields below 50 kV/cm and saturate at ∼ 1 THz above 50 kV/cm at 300 K. From the temperature dependence of νc, it is found that νc is governed by the emission of optical phonons.
Show PACS
78.70.Gq Microwave and radio-frequency interactions
78.47.-p Spectroscopy of solid state dynamics
63.20.D- Phonon states and bands, normal modes, and phonon dispersion
FREE

Low temperature diffusion length of excitons in gallium nitride measured by cathodoluminescence technique

Naoyuki Ino and Naoki Yamamoto

Appl. Phys. Lett. 93, 232103 (2008); http://dx.doi.org/10.1063/1.3040310 (3 pages) | Cited 7 times

Online Publication Date: 10 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monochromatic cathodoluminescence (CL) images of threading dislocations in GaN epitaxial layers were observed using a transmission electron microscopy combined with CL system. The carrier diffusion lengths were derived from the free exciton emission intensity profile of the dislocation contrast in the CL images. The carrier diffusion lengths in Si-doped and Mg-doped GaN were nearly the same and shorter than that in undoped GaN in the temperature range from 20 to 140 K, respectively. Moreover, the temperature dependence of the diffusion length shows that the acoustic phonon scattering mainly affects the exciton diffusion process at low temperatures from 40 to 120 K.
Show PACS
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
78.60.Hk Cathodoluminescence, ionoluminescence
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
71.35.-y Excitons and related phenomena
FREE

The chemical and electronic surface and interface structure of CuGaSe2 thin-film solar cell absorbers

M. Bär, M. Rusu, S. Lehmann, Th. Schedel-Niedrig, I. Lauermann, and M. C. Lux-Steiner

Appl. Phys. Lett. 93, 232104 (2008); http://dx.doi.org/10.1063/1.2998391 (3 pages) | Cited 4 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The chemical and electronic surface and interface structure of CuGaSe2 thin films was investigated by photoelectron spectroscopy. With bulk [Ga]/[Cu] ratios increasing from 0.94 to 1.39 a transition of the Cu:Ga:Se surface composition from 1:1:2 to 1:3:5 and a downward shift of the valence band maximum with respect to the Fermi energy were observed. The comparison with the conduction band minimum (CBM) of CdS reveals that at the CdS/CuGaSe2 interface the recombination barrier height simultaneously increases and a “clifflike” offset is formed to the CBM of CuGaSe2.
Show PACS
73.20.At Surface states, band structure, electron density of states
68.47.Fg Semiconductor surfaces
84.60.Jt Photoelectric conversion
79.60.Bm Clean metal, semiconductor, and insulator surfaces
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
68.35.Dv Composition, segregation; defects and impurities
FREE

Charge loss behavior of a metal-alumina-nitride-oxide-silicon-type flash memory cell with different levels of charge injection

Man Chang, Minseok Jo, Seonghyun Kim, Yongkyu Ju, Seungjae Jung, Joonmyoung Lee, Jaesik Yoon, Hyunsang Hwang, and Choongman Lee

Appl. Phys. Lett. 93, 232105 (2008); http://dx.doi.org/10.1063/1.3041642 (3 pages) | Cited 6 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We found that the charge loss behavior of metal-alumina-nitride-oxide-silicon-type flash memory was highly dependent on the amount of injected charge (Qinj). Beyond the critical level of Qinj, the direction of the dominant charge loss changed from pointing toward SiO2 to pointing toward Al2O3. The highly injected charges could cause the band bending of Al2O3, which reduced the tunneling distance across Al2O3 with the low conduction band offset. These results were verified by experimental results and theoretical device modeling through a comparison of the charge loss rate and the tunneling rate between a SiO2/Si3N4/SiO2 stack and a SiO2/Si3N4/Al2O3 stack.
Show PACS
84.30.Sk Pulse and digital circuits
back to top
RSS Feeds
FREE

Composition dependence of magnetocaloric effect in Sm1−xSrxMnO3(x = 0.3–0.5)

A. Rebello and R. Mahendiran

Appl. Phys. Lett. 93, 232501 (2008); http://dx.doi.org/10.1063/1.3040698 (3 pages) | Cited 27 times

Online Publication Date: 8 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated magnetic and magnetocaloric properties in Sm1−xSrxMnO3(x = 0.3–0.5). We report a magnetic field-driven first-order metamagnetic transition in the paramagnetic state in x = 0.4 and 0.5 and a second-order transition in x = 0.3. The highest magnetic entropy (−ΔSm = 1.41 J/mol K for ΔH = 5 T at T = 125 K) that occurs in x = 0.4 is associated with the metamagnetic transition resulting from the field-induced growth and coalescence of ferromagnetic nanoclusters pre-existing in the paramagnetic state. Our results suggest that manganites with intrinsic nanoscale phase separation can be exploited for magnetic refrigeration.
Show PACS
75.47.Lx Magnetic oxides
65.40.gd Entropy
75.47.Gk Colossal magnetoresistance
FREE

Electric detection of ferromagnetic resonance in single crystal iron film

Xiong Hui, A. Wirthmann, Y. S. Gui, Y. Tian, X. F. Jin, Z. H. Chen, S. C. Shen, and C.-M. Hu

Appl. Phys. Lett. 93, 232502 (2008); http://dx.doi.org/10.1063/1.3029744 (3 pages) | Cited 5 times

Online Publication Date: 8 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report electric detection of ferromagnetic resonance (FMR) in epitaxially grown single crystal iron film through microwave photovoltage generation technique. The experimental results agree well with the established theory about FMR in iron films, showing excellent extendability of such a technique onto different ferromagnets as an effective way to study magnetocrystalline anisotropy and spin excitations. Furthermore, the information about the phase of magnetization precession is implicated in the lineshape of photovoltage, which makes it possible to probe in details into magnetic phase dynamics that is of significance for devising spintronic devices.
Show PACS
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.30.Gw Magnetic anisotropy
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
FREE

Atomic ordering and magnetic properties in the Ni45Co5Mn36.7In13.3 metamagnetic shape memory alloy

W. Ito, M. Nagasako, R. Y. Umetsu, R. Kainuma, T. Kanomata, and K. Ishida

Appl. Phys. Lett. 93, 232503 (2008); http://dx.doi.org/10.1063/1.3043456 (3 pages) | Cited 22 times

Online Publication Date: 9 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of chemical order on the phase stability and magnetic properties of the metamagnetic shape memory alloy Ni45Co5Mn36.7In13.3 were investigated. Alloys quenched from the B2 and L21 phase regions were found to transform to the L10 and 6M martensite phases, respectively. For alloys quenched from the B2 region the martensitic transformation starting temperature is about 80 K higher than that for alloys quenched from the L21 region. The Curie temperature of the parent phase and the magnetization of the martensite phase were both lower for the alloy quenched from the B2 region than those for the alloy quenched from L21 region.
Show PACS
81.30.Kf Martensitic transformations
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
64.70.kd Metals and alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Cr Saturation moments and magnetic susceptibilities
FREE

Ferromagnetic structurally disordered ZnO implanted with Co ions

K. Potzger, Shengqiang Zhou, Qingyu Xu, A. Shalimov, R. Groetzschel, H. Schmidt, A. Mücklich, M. Helm, and J. Fassbender

Appl. Phys. Lett. 93, 232504 (2008); http://dx.doi.org/10.1063/1.3040696 (3 pages) | Cited 10 times

Online Publication Date: 10 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present superparamagnetic clusters of structurally highly disordered Co–Zn–O created by high fluence Co ion implantation into ZnO (0001) single crystals at low temperatures. This secondary phase cannot be detected by common x-ray diffraction but is observed by high-resolution transmission electron microscopy. In contrast to many other secondary phases in a ZnO matrix, it induces low-field anomalous Hall effect and is thus a candidate for magnetoelectronics applications.
Show PACS
61.72.uj III-V and II-VI semiconductors
75.20.-g Diamagnetism, paramagnetism, and superparamagnetism
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Pp Magnetic semiconductors
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
FREE

Coherent control of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As

E. Rozkotová, P. Němec, N. Tesařová, P. Malý, V. Novák, K. Olejník, M. Cukr, and T. Jungwirth

Appl. Phys. Lett. 93, 232505 (2008); http://dx.doi.org/10.1063/1.3046718 (3 pages) | Cited 8 times

Online Publication Date: 12 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report single-color, time-resolved magneto-optical measurements in ferromagnetic semiconductor (Ga,Mn)As. We demonstrate coherent optical control of the magnetization precession by applying two successive ultrashort laser pulses. The magnetic field and temperature dependent experiments reveal the collective Mn-moment nature of the oscillatory part of the time-dependent Kerr rotation, as well as contributions to the magneto-optical signal that are not connected with the magnetization dynamics.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
78.20.Ls Magneto-optical effects
78.47.-p Spectroscopy of solid state dynamics
75.50.Pp Magnetic semiconductors
FREE

Current-induced flip-flop of magnetization in magnetic tunnel junction with perpendicular magnetic layers and polarization-enhancement layers

Woojin Kim, Taek Dong Lee, and Kyung-Jin Lee

Appl. Phys. Lett. 93, 232506 (2008); http://dx.doi.org/10.1063/1.3046729 (3 pages) | Cited 3 times

Online Publication Date: 12 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We performed a micromagnetic investigation of current-induced magnetization switching in perpendicular magnetic tunnel junctions with polarization-enhancement layers. The pinned layer with a polarization-enhancement layer can be excited and eventually reverses at a current density lower than the value theoretically expected from that without a polarization-enhancement layer. The reversal results in continuous flip-flops of magnetizations as long as the current is applied. The flip-flop occurs at only one current polarity, caused by the precession amplification in polarization-enhancement layer. In order to prevent the unwanted flip-flop, the perpendicular anisotropy of the pinned layer must be severalfold larger than that of the free layer.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Jk Magnetization reversal mechanisms
85.75.Dd Magnetic memory using magnetic tunnel junctions
FREE

Room temperature ferromagnetism in carbon-implanted ZnO

Shengqiang Zhou, Qingyu Xu, Kay Potzger, Georg Talut, Rainer Grötzschel, Jürgen Fassbender, Mykola Vinnichenko, Jörg Grenzer, Manfred Helm, Holger Hochmuth, Michael Lorenz, Marius Grundmann, and Heidemarie Schmidt

Appl. Phys. Lett. 93, 232507 (2008); http://dx.doi.org/10.1063/1.3048076 (3 pages) | Cited 64 times

Online Publication Date: 12 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Unexpected ferromagnetism has been observed in carbon doped ZnO films grown by pulsed laser deposition [ H. Pan et al., Phys. Rev. Lett. 99, 127201 (2007) ]. In this letter, we introduce carbon into ZnO films by ion implantation. Room temperature ferromagnetism has been observed. Our analysis demonstrates that (1) C-doped ferromagnetic ZnO can be achieved by an alternative method, i.e., ion implantation, and (2) the chemical involvement of carbon in the ferromagnetism is indirectly proven.
Show PACS
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
81.20.-n Methods of materials synthesis and materials processing
back to top
RSS Feeds
FREE

Phase-specific magnetic ordering in BiFeO3−PbTiO3

Tim P. Comyn, Tim Stevenson, Maisoon Al-Jawad, Stuart L. Turner, Ronald I. Smith, William G. Marshall, Andrew J. Bell, and Robert Cywinski

Appl. Phys. Lett. 93, 232901 (2008); http://dx.doi.org/10.1063/1.3042209 (3 pages) | Cited 3 times

Online Publication Date: 9 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The multiferroic 0.7 BiFeO3–0.3 PbTiO3 has been fabricated in both sintered ceramic and powder form using conventional mixed oxide synthesis. Rietveld’s analysis of neutron powder diffraction data has shown that the sintered ceramic and powder are predominantly R3c and P4mm phases, respectively. It is shown explicitly that magnetic ordering does not occur for the P4mm phase at room temperature.
Show PACS
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)
75.30.Cr Saturation moments and magnetic susceptibilities
75.50.Tt Fine-particle systems; nanocrystalline materials
61.43.Gt Powders, porous materials
FREE

Glasslike state in PbFe1/2Nb1/2O3 single crystal

Ashok Kumar, R. S. Katiyar, Carlos Rinaldi, Sergey G. Lushnikov, and Tatjana A. Shaplygina

Appl. Phys. Lett. 93, 232902 (2008); http://dx.doi.org/10.1063/1.3043686 (3 pages) | Cited 7 times

Online Publication Date: 9 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetic properties of PbFe1/2Nb1/2O3 single crystal showed onset of glasslike behavior at 120 K, saturation of onset at 28 K, and freezing of glasslike state at 27.6 K. Zero field cooled (ZFC) and field cooled magnetization curves displayed sharp cusp in ZFC. Almeida and Toulouse line illustrated stability over 1000 Oe with unstable onset for low field. Magnetic hysteresis was observed below glasslike freezing temperature having steplike behavior and low coercive field ∼ 296 Oe, which may be due to chemical inhomogeneity, strong anisotropy, and weak dipole interaction.
Show PACS
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Lk Spin glasses and other random magnets
75.70.-i Magnetic properties of thin films, surfaces, and interfaces
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
FREE

Transmission electron microscopic study of the long period modulated phase in the morphotropic phase-boundary region of (1−x)NaNbO3–xCaTiO3 for x = 0.16

Saurabh Tripathi, N. P. Lalla, and Dhananjai Pandey

Appl. Phys. Lett. 93, 232903 (2008); http://dx.doi.org/10.1063/1.3037223 (3 pages)

Online Publication Date: 10 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The recently reported structure of the long period modulated phase of (1−x)NaNbO3–xCaTiO3, with x = 0.16, has been revisited using transmission electron microscopic studies. It is shown that the dominant phase in the morphotropic phase boundary region of this mixed system is incommensurately modulated in the [001] direction with an approximate unit cell size of 2ap×2ap×24ap, where ap is the pseudoperovskite cell parameter.
Show PACS
61.66.Fn Inorganic compounds
61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.80.-e Ferroelectricity and antiferroelectricity
FREE

Misfit strain–misfit strain diagram of epitaxial BaTiO3 thin films: Thermodynamic calculations and phase-field simulations

G. Sheng, J. X. Zhang, Y. L. Li, S. Choudhury, Q. X. Jia, Z. K. Liu, and L. Q. Chen

Appl. Phys. Lett. 93, 232904 (2008); http://dx.doi.org/10.1063/1.3039410 (3 pages) | Cited 8 times

Online Publication Date: 11 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of anisotropic strains on the phase transitions and domains structures of BaTiO3 thin films was studied using both thermodynamic calculations and phase-field simulations. The misfit strain–misfit strain domain stability diagrams were predicted. The similarity and significant differences between the diagrams from thermodynamic calculations assuming single domains and from phase-field simulations were analyzed. Typical domain structures as a result of anisotropic misfit strains are presented.
Show PACS
77.55.-g Dielectric thin films
77.80.B- Phase transitions and Curie point
77.80.Dj Domain structure; hysteresis
FREE

Dielectric properties of Ba0.5Sr0.5TiO3/SiN bilayered thin films grown on Pt-coated sapphire substrates

Niandeng Xiong, Shuwen Jiang, Yanrong Li, Lefan Tan, and Ruguan Li

Appl. Phys. Lett. 93, 232905 (2008); http://dx.doi.org/10.1063/1.3049127 (3 pages) | Cited 7 times

Online Publication Date: 12 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Ba0.5Sr0.5TiO3(BST)/SiN bilayered thin films with a SiN layer serving as a buffer layer between the top electrode and the BST layer have been prepared onto Pt-coated c-plane sapphire substrates. The dielectric measurements show that the loss tangent has been significantly lowered. The dielectric properties of the BST/SiN bilayered thin films are strongly dependent on the SiN thickness. The BST/SiN bilayered thin films at a SiN/BST thickness ratio of 0.2 give the largest figure of merit of 50.1. The thickness effect was discussed as well with a series connection model of multilayered capacitors, and the favorable simulation was obtained.
Show PACS
84.32.Tt Capacitors
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
77.55.-g Dielectric thin films
77.22.Gm Dielectric loss and relaxation
back to top
RSS Feeds
FREE

Energy gap modulation in V2O5 nanowires by gas adsorption

Byung Hoon Kim, Ansoon Kim, Soon-Young Oh, Sung-Soo Bae, Yong Ju Yun, and Han Young Yu

Appl. Phys. Lett. 93, 233101 (2008); http://dx.doi.org/10.1063/1.3044403 (3 pages) | Cited 5 times

Online Publication Date: 8 December 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The current-voltage characteristics at various pressures (2–10 atm) and the scanning tunneling microscopy of vanadium pentoxide nanowires (VONs) with the inert gases (He, Ne, and Ar) and diatomic molecules (H2, N2, O2) have been investigated. The gas dependent conductance (G) is consistent with the inverse energy gap obtained from the scanning tunneling spectroscopy study for the gas-adsorbed single VON. The three possible interactions for gas adsorption of the VON have been discussed. Among them, we have found that the induced dipole-dipole interaction between adsorbed gases plays an important role in conductance variation in the gas adsorbed VON using the conductance per molecule (G/N).
Show PACS
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
68.47.-b Solid-gas/vacuum interfaces: types of surfaces
73.63.Nm Quantum wires
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close