Perpendicular resistance and galvanomagnetic effect in metallic superlattices

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1) On the temperature dependences of resistivity and Hall coefficient of small layer periodicity (LAMBDA) Cu/Ni superlattices, we first observed structures characteristic of the decrease of Curie temperature. We also found this system is one the family of the superlattices with giant magnetoresistance (up to 9.3% for LAMBDA=2.75nm).2) While the Cr thickness is varied from 1 monatomic layer to 6 ML, the Hall coefficient enhanced and has a peak of about 3 times of pure Ag value at 3 ML.3) For Au/Mn system, we observed an enhancement of Hall coefficient with decreasing temperature down to about 20K. Together with the negative magnetoresistance observed at low temperature, it suggests there is magnetic conduction electron scattering with two dimensional character. From the temperature dependence of Hall coefficient, Mn layer in Au (30) /Mu (60) is decided to be alpha 4 phase which could not be identified by the other methods.4) On Pd/Co sample with a perpendicular anisotropy, we first observed the squared hysteresis loop directly on the field dependence of Hall resistivity.5) In Fe/Cr system, we first observed the clear correlation between the negative magnetoresistance and the anomalous Hall effect.6) For the perpendicular resistivity measurement, we still have some problems. We, however, could use this method to decide whether the specular transmission or the specular reflection of conduction electrons at interfaces of Ag/Co multilayer is dominant. Form the extra resistivity measured in the perpendicular geometry, the specular transmission is judged to predominate in this system.