Anisotropic magnetoresistance in La0.75Sr0.25MnO3/LaNiO3 trilayers

M. GRANADA; J. C. ROJAS SÁNCHEZ; L. B. STEREN

Buenos Aires, Argentina

Workshop; At the Frontiers of Condensed Matter III; 2006

Ferromagnetic manganites are interesting compounds to be used in magnetorresistive devices due to their half-metallic character. Moreover, there are a large number of compounds with the same crystalline structure but dierent magnetic and electric properties. La0.75Sr0.25MnO3 (LSMO) is ferromagnetic and metallic below its Curie temperature and LaNiO3 (LNO) presents Pauli paramagnetism and is metallic. For this study we grew metallic trilayers LSMO/LNO/LSMO on (100) SrTiO3 single crystalline substrates, aiming to the fabrication of giant magnetoresistance (GMR) devices. In a previous work, we studied the magnetic coupling between the LSMO layers in these samples. Once the samples were magnetically characterized, we performed in-plane electric transport measurements. In-plane GMR is weak and so other effects contributing to the low- field magnetoresistance should be carefully taken into account in analyzing the measured data. The anisotropic magnetoresistance (AMR) is an effect that depends on the angle between the magnetization and the electrical current, and its magnitude is important in manganite films. We studied the AMR on reference LSMO thin films and LSMO/LNO/LSMO trilayers. We found that the general features of the AMR observed in LSMO films appear in trilayers. The differences in the shape of the magnetoresistance curves of the trilayers, in comparison to that of the LSMO films are attributed to the GMR effect.