Anisotropic magnetoresistance and spin polarization of La0.7Sr0.3MnO3/SrTiO3 superlattices -: art. no. 172503

The crystalline structure, anisotropic magnetoresistance (AMR), and magnetization of La0.7Sr0.3MnO3/SrTiO3 (LSMO/STO) superlattices grown by a rf sputtering system are systematically analyzed to study the spin polarization of manganite at interfaces. The presence of positive low-temperature AMR in LSMO/STO superlattices implies that two bands of majority and minority character contribute to the transport properties, leading to a reduced spin polarization. Furthermore, the magnetization of superlattices follows the T-3/2 law and decays more quickly as the thickness ratio d(STO)/d(LSMO) increases, corresponding to a reduced exchange coupling. The results clearly show that the spin polarization is strongly correlated with the influence of interface-induced strain on the structure. (C) 2005 American Institute of Physics.