Quantum effects in atomically perfect specular spin valve structures (2007)
Teixeira, J. M., Ventura, J., Pogorelov, Yu. G., Sousa, J. B.
A simple tight-binding theoretical model is proposed for spin dependent, current-in-plane transport in highly coherent spin valve structures under specularity conditions. Using quantum-mechanically...
Ventura, J., Zhang, Z., Liu, Y., Sousa, J. B., Freitas, P. P.
Current Induced Resistance Switching (CIS) was recently observed in thin tunnel junctions (TJs) with ferromagnetic (FM) electrodes and attributed to electromigration of metallic atoms in...
Ventura, J., Ferreira, R., Sousa, J. B., Freitas, P. P.
Magnetic tunnel junctions (MTJs) with partially oxidized 9 \AA AlO$_x$-barriers were recently shown to have the necessary characteristics to be used as magnetoresistive sensors in high-density...
Nanoscopic processes of Current Induced Switching in thin tunnel junctions (2006)
Ventura, J., Araujo, J. P., Sousa, J. B., Liu, Y., Zhang, Z., Freitas, P. P.
In magnetic nanostructures one usually uses a magnetic field to commute between two resistance (R) states. A less common but technologically more interesting alternative to achieve R-switching is to...
Domain imaging, MOKE and magnetoresistance studies of CoFeB films for MRAM applications (2005)
Teixeira, J. M., Silva, R. F. A., Ventura, J., Pereira, A. M., Carpinteiro, F., Araujo, J. P., ...
We present a detailed study on domain imaging, Kerr effect magnetometry (MOKE) and magnetoresistance (MR), for a series of 20 nm Co$_{73.8}$Fe$_{16.2}$B$_{10}$ thin films, both as-deposited...
Teixeira, J. M., Silva, R. F. A., Ventura, J., Pereira, A., Araujo, J. P., Amado, M., ...
A MOKE magnetometry unit simultaneously sensitive to both in-plane magnetization components, based on an intensity differential detection method, allows us to observe the uniaxial anisotropy...
Anomalous magnetoresistance behavior of CoFe nano-oxide spin valves at low temperatures (2005)
Ventura, J., Sousa, J. B., Freitas, P. P., Veloso, A.
We report magnetoresistance curves of CoFe nano-oxide specular spin valves of MnIr/CoFe/nano-oxidized CoFe/CoFe/Cu/CoFe/nano-oxidized CoFe/Ta at different temperatures from 300 to 20 K. We extend the...
Ventura, J., Sousa, J. B., Liu, Y., Zhang, Z., Freitas, P. P.
Current Induced Resistance Switching (CIS) was recently observed in thin tunnel junctions with ferromagnetic (FM) electrodes \emph{i.e} FM/I/FM. This effect was attributed to electromigration of...
Neutron star envelopes and thermal radiation from the magnetic surface (2001)
The thermal structure of neutron star envelopes is discussed with emphasis on analytic results. Recent progress on the effect of chemical constitution and high magnetic fields on the opacities and...
The supernova remnants G67.7+1.8, G31.5-0.6 and G49.2-0.7 (2001)
Mavromatakis, F., Papamastorakis, J., Ventura, J., Becker, W., Paleologou, E. V., Schaudel, D.
Wide field CCD observations of three, less known, supernova remnants. Filamentary and diffuse emission is discovered from the supernova remnant G67.7+1.8. Emission can also be seen in the ROSAT All...
The peculiar supernova remnant CTB 80 (2001)
Mavromatakis, F., Ventura, J., Paleologou, E. V., Papamastorakis, J.
Deep CCD exposures of the peculiar supernova remnant CTB 80 in the light of major optical lines have been obtained. These images reveal significant shock heated emission in the area of the remnant....
Ionization equilibrium and equation of state of hydrogen plasmas in strong magnetic fields (1998)
Potekhin, A. Y., Chabrier, G., Shibanov, Yu. A., Ventura, J.
We study hydrogen plasmas at magnetic fields B ~ 10^{12}-10^{13} Gauss, densities ~ 10^{-3}-10^3 g/cc and temperatures T ~ 10^{5.5}-10^{6.5} K, typical of photospheres of middle-aged cooling neutron...
Potekhin, A. Y., Shibanov, Yu. A., Ventura, J.
We study partially ionized hydrogen plasma at temperatures T = 10^{5.5}-10^{6.5} K and magnetic fields B = 10^{12}-10^{13} G, typical of photospheres of isolated neutron stars. We construct an...
Ionization of the hydrogen atom in strong magnetic fields: beyond the adiabatic approximation (1996)
Potekhin, A. Y., Pavlov, G. G., Ventura, J.
High magnetic fields in neutron stars, B ~ 10^{11} - 10^{13} G, substantially modify the properties of atoms and their interaction with radiation. In particular, the photoionization cross section...
A Representative Consumer Theory of Distribution.
This paper shows that growth models featuring the representative consumer (RC) assumption can generate rich dynamics for the cross-sections of consumption, wealth and income. We consider a class of...
A Representative Consumer Theory of Distribution.
This paper shows that growth models featuring the representative consumer (RC) assumption can generate rich dynamics for the cross- sections of consumption, wealth and income.
Current Acounts in Debtor and Creditor Countries.
This paper reexamines a classic question in international economics: What is the current account response to a transitory income shock such as a temporary improvement in the terms of trade, a tranfer...
The Leontief-Trefler Hypothesis and Factor Price Insensitivity.
This paper reports the results of a new test of the Leontief-Trefler hypothsis that factor-augmenting international productivity differences explain most of the cross-country variation in factor...