Copper-doped lanthanum manganite LaCeSrMn Cu O influence on structural, magnetic and magnetocaloric effects.

Bulk nanocrystalline samples of LaCeSrMn Cu O (0 ≤ ≤ 0.15) manganites are prepared by the sol-gel based Pechini method. The effect of the substitution for Mn with Cu upon the structural and magnetic properties has been investigated by means of X-ray diffraction (XRD), Raman spectroscopy and dc magnetization measurements.

Towards InAs/InGaAs/GaAs Quantum Dot Solar Cells Directly Grown on Si Substrate.

This paper reports on an initial assessment of the direct growth of In(Ga)As/GaAs quantum dots (QDs) solar cells on nanostructured surface Si substrate by molecular beam epitaxy (MBE). The effect of inserting 40 InAs/InGaAs/GaAs QDs layers in the intrinsic region of the heterojunction pin-GaAs/n⁺-Si was evaluated using photocurrent spectroscopy in comparison with pin-GaAs/n⁺-Si and pin-GaAs/GaAs without QDs. The results reveal the clear contribution of the QDs layers to the improvement of the spectral response up to 1200 nm.

Water-silica gel interactions, X-ray diffraction study at room and low temperature.

X-ray diffraction experiments on water confined in silica gel powder hydrated at about 20% are presented and analyzed at room temperature and down to 77 K. The structural modification of confined water observed at second neighbors is due to the competition between the confinement effect and the water-silica interaction.