Hall effect in manganites films

M. GRANADA; M. SIRENA; L. B. STEREN; J. GUIMPEL

S. C. de Bariloche

Workshop; V Latin American Workshop on Magnetism, Magnetic Materials and their Applications; 2001

The influence of the sample size on the Hall effect has been investigated for thin films of A0.67B0.33MnO3 (A: La; B: Sr, Ca). These manganites compounds are ferromagnets below room temperature and present a metal-insulator transition close to the Curie point. For the present study a series of films with thickness varying from 10nm to 300nm have been grown by dc sputtering. The samples were grown on two different substrates, (100) MgO and (100) SrTiO3, both of cubic structures. X-ray diffraction patterns indicate that films grow strongly textured in the (100) direction perpendicular to the film surface. ac and dc measurements of the Hall effect were performed in magnetic fields up to 9T and temperature range between 4.2K and 300K. The temperature dependence of the ordinary and anomalous Hall coeficients have been analized. These results together with complementary magnetoresistance data serve to clarify the scattering mechanisms present in this kind of systems and the carriers nature and density. Magnetization measurements have been also performed and the results correlated with transport ones.