Defect-induced room temperature ferromagnetism in un-doped InN film

Q. Y. Xie, M. Q. Gu, L. Huang, F. M. Zhang, and X. S. Wu

Here we show epitaxial InN film, a well-known narrow gap semiconductor can be ferromagnetic without doping. The Curie temperature acquired is as high as 297K and the magnetic moment is 1.6μB, spawning a whole new class of potential room temperature DMS (diluted magnetic semiconductors).

AIP Advances 2, 012185 (2012)

Intrinsic thermoelectric power of group VB metals

Gunadhor Singh Okram

Reinvestigations of the thermopower α of group VB metals in polycrystalline forms in the temperature range of 6-300K revealed the critical nature of the sample surface contaminations and heat treatment especially for niobium. Strikingly small magnitude, negative sign, phonon drag dip and superconductivity not reported previously were observed in surface-cleaned single crystalline Nb. However, while thermopower magnitudes are small, mixed signs were found in the polycrystalline V, Nb and Ta samples.

AIP Advances 2, 012178 (2012)

Ambient organic molecular passivation of Si yields near-ideal, Schottky-Mott limited, junctions

Rotem Har-Lavan, Omer Yaffe, Pranav Joshi, Roy Kazaz, Hagai Cohen, and David Cahen

The authors show how a simple, short chemical treatment, done in air, to adsorb a molecular monolayer onto the Si, pulls the semiconductor back into the fold of “well-behaved” semiconductors that obey the Schottky-Mott model. Nearly all of the systematic change in electrical behaviour of the Si surface, as a result of different molecular treatments, can be transferred to its interface with a metal, Hg in this case. Thus, for the first time, Si junction behavior could be predicted from the measured properties of its components according to the Schottky-Mott model.

AIP Advances 2, 012164 (2012)

Semiclassical Monte Carlo simulation studies of spin dephasing in InP and InSb nanowires

Ashish Kumar, M. W. Akram, and Bahniman Ghosh

A multisubband semiclassical Monte Carlo approach was used to investigate spin polarized transport in InP and InSb nanowires. The authors found the dephasing rate to be very strong for InSb as compared to InP which has larger spin dephasing lengths. The ensemble averaged spin components varied differently for both InP and InSb nanowires. The steady state spin distribution also showed a difference between the two III-V nanowires.

AIP Advances 2, 012165 (2012)

Triggering, guiding and deviation of long air spark discharges with femtosecond laser filament

B. Forestier, A. Houard, I. Revel, M. Durand, Y. B. André, B. Prade, A. Jarnac, J. Carbonnel, M. Le Nevé, J. C. de Miscault, B. Esmiller, D. Chapuis, and A. Mysyrowicz

The ability of femtosecond laser filaments to deviate long air gap spark discharge from their natural point of attachment is demonstrated. Laser filaments were also able to divert the spark without contact between laser and electrodes at large distance from the laser. A comparison between negative and positive discharge polarities also reveals important discrepancies in the guiding mechanism.

AIP Advances 2, 012151 (2012)
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Spherical magnetic nanoparticles fabricated by electric explosion of wire

G. V. Kurlyandskaya, S. M. Bhagat, A. P. Safronov, I. V. Beketov, and A. Larrañaga

Iron oxide magnetic nanoparticles were prepared by the electrophysical method of electric explosion of wire which can be considered a green alternative without the use of toxic solvents, surfactants and water. The rate of production by this method was found to be very high (100g per hour) which is advantageous when a large amount of material is needed for applications. The structural features, magnetic properties and microwave absorption of these biocompatible nanoparticles clearly indicated that their shape is very close to being spherical, thus, making them potentially useful for biomedical applications.

AIP Advances 1, 042122 (2011)

Hot spin spots in the laser-induced demagnetization

M. S. Si and G. P. Zhang

Today's computers use the spin procession reversal triggered by a magnetic field to write data to disks on millisecond timescales. Femtosecond magnetism relies on the ultrafast laser pulse to manipulate the spin change. The authors propose a concept called optical spin generator to examine hot spin spots comprehensively. This allows a direct access to spin change in the crystal-momentum space. They show the first details of how spin change in ferromagnetic Ni evolve at timescales of a quadrillionth of a second.

AIP Advances 2, 012158 (2012)

Linear and nonlinear intraband optical properties of ZnO quantum dots embedded in SiO₂ matrix

Deepti Maikhuri, S. P. Purohit, and K. C. Mathur

The authors investigated optical properties of semiconductor ZnO spherical quantum dot embedded in an amorphous SiO₂ dielectric matrix. The authors found that dot size, confinement potential, and incident radiation intensity affect intraband optical properties of the dot significantly.

AIP Advances 2, 012160 (2012)

Time response of Cd_0.9Zn_0.1Te crystals under transient and pulsed irradiation

X. C. Zhao, X. P. Ouyang, Y. D. Xu, H. T. Han, Z. C. Zhang, T. Wang, G. Q. Zha, and X. Ouyang

The authors developed and tested a CdZnTe detector based on high-quality Cd_0.9Zn_0.1Te crystals as a monitor in high-intensity radiation fields. The results show that the CdZnTe detector has a fast time response, with a rise time of approximately 2 ns, when exposed to transient and pulsed irradiation of X-rays or electron beams.

AIP Advances 2, 012162 (2012)

The role of Mg interface layer in MgO magnetic tunnel junctions with CoFe and CoFeB electrodes

Hyunsoo Yang, See-Hun Yang, and Stuart Parkin

By using superconducting tunneling spectroscopy, the authors study the function of Mg interface layers in crystalline MgO tunnel junctions with various CoFe and CoFeB electrodes on the tunneling spin polarization (TSP). They find that the dependence of the TSP values on Mg interface layer thickness for CoFeB/Mg/MgO junctions is substantially different from those for CoFe/Mg/MgO.

AIP Advances 2, 012150 (2012)