LaSrMnOfilms are deposited on(001) silicon substrates,in which the silicon surfaces have artificially been treated into the scallops-like,pyramid-like,and smooth polishing structure,by pulsed laser deposition.The magnetoresistances of the films on etched substrates under low applied field are very sensitive to the applied field,and much larger(14.3% for acid-etched,and 42.9% for alkali-etched) than that on the polished Si at 5 K.Zero-field-cooled and field-cooled magnetization behaviors are measured and analyzed.Remarkable upturn behaviors in temperature-dependent resistivity for all samples are observed at low temperature,which follows the Efros-Shkloskii variable range hopping law and the Arrhenius law.We believe that the rough surface may be useful in device design.
Combined with the rough textures which are usually used for fabricating the planar solar cells, textured-microwire（MW） structures（there are MW textures on the tops of MWs） are fabricated. Both simulative and experimental investigations of the optical properties of Si surface with microwires are carried out and the results show that surfaces of texturedMW structures exhibit lower reflectance in the short wavelength range, but higher reflectance in the long wavelength range than the conventional textured surface. It is also shown, consequently, that the textured-MW structures could absorb more photons in the short wavelength range, which could help improve the performance of the solar cells.
The pseudopotential method has been used to investigate the structural, electronic and magnetic properties of La1-xEuxGaO3 （x = 0, 0.25, 0.5, 0.75, and 1） within the scheme of generalized gradient approximation. The spin-polarized calculations demonstrate that the ground state is an antiferromagnetic insulator for x ≤ 0.5, while it is ferromagnetic halfmetal at x 〉 0.5. The substitutions of magnetic Eu ions for non-magnetic La ions produce and strength spin polarization, which forcefully urges the system from the insulator to the half metal. Meanwhile, Eu doping strengthens a stoner mechanism for ferromagnetism of La1-xEuxGaO3 （x = 0.75 and 1）, which may lead to a rapid increasing in the total magnetic moment and therefore, antiferromagnetic-ferromagnetic transition happens.
