GERENCIA FÍSICA

URI permanente para esta comunidad

https://nuclea.cnea.gob.ar/handle/20.500.12553/5207

Examinar

Examinando GERENCIA FÍSICA por Autor "Alascio, B."

Mostrando 1 - 2 de 2
  • Miniatura
    ÍtemAcceso Abierto
    Magnetoresistance effect in (La, Sr)MnO3 bicrystalline films
    (IOP Publishing, 2010-08-10) Alejandro, G.; Steren, L. B.; Pastoriza, H.; Vega, D.; Granada, M.; Rojas Sánchez, J. C.; Sirena, M.; Alascio, B.; Gerencia Física. Departamento Materia Condensada. División Bajas Temperaturas
    The angular dependence of the magnetoresistance effect has been measured on bicrystalline La0.75Sr0.25MnO3 films. The measurements have been performed on an electronically lithographed Wheatstone bridge. The study of the angular dependence of both the magnetoresistance and the resistance of single-crystalline and grain-boundary regions of the samples allowed us to isolate two contributions of low-field magnetoresistance in manganites. One of them is associated with the spin–orbit effect, i.e. the anisotropic magnetoresistance of ferromagnetic compounds, and the other one is related to spin-disorder regions at the grain boundary. Complementary x-ray diffraction, ferromagnetic resonance and low temperature magnetization experiments contribute to the characterization of the magnetic anisotropy of the samples and the general comprehension of the problem.
  • Miniatura
    ÍtemAcceso Abierto
    Unusual large magnetostriction in the ferrimagnet Gd2/3Ca1/3MnO3
    (IOP Publishing, 2012-00-00) Correa,V. F.; Haberkorn, N.; Nieva, G.; García, D. J.; Alascio, B.; Gerencia Física. Departamento Materia Condensada. División Bajas Temperaturas
    We report an unusual large linear magnetostrictive effect in the ferrimagnet Gd2/3Ca1/3MnO3 (Tc≈80 K). Remarkably, the magnetostriction, negative at high temperature (T≈Tc), becomes positive below 15 K when the magnetization of the Gd sublattice overcomes the magnetization of the Mn sublattice. A rather simple model where the magnetic energy competes against the elastic energy gives a good account of the observed results and confirms that Gd plays a crucial role in this unusual observation. Unlike previous works in manganites where only striction associated with 3d Mn orbitals is considered, our results show that the lanthanide 4f-orbitals–related striction can be very important too and it cannot be disregarded.