A comprehensive transport investigations on the systems exhibiting the giant magnetoresistance

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(1)To investigate how the spin-glass transition compete with the interlayr coupling in magnetic multilayrs, we have measured the magnetization, magnetoresistance (MR), Hall effect and thermoelectric power of Cu (Mm) /Co multilayrs. We found a clear evidence of the competition such as an increment of the saturation field. Most prominent feature was found on the sample with Cu (Mn) layr thickness near 15A where we expect a ferromagnetic coupling as in the sample with pure Cu layrs. The coupling was ferromagnetic at room temeprature, however, an antiferromagnetic component grew enormously below 70K.The result can be understood partially as due to the combined effect of the spin-glass transition and the interlayr coupling. (2) We previously reported that the large field dependence of scattering probability of conduction electron appeared in the anomalous Hall resistivity. However, it is not settled yet. In order to make sure the fact, we made simultaneous measurements of the Hall effect and MR on CO (Fe) /Cu multilayrs which exhibits the MR oscillation most clearly. We found a clear oscillation of anomalous Hall coefficient synchronized with the MR oscillation. We also found a synchronized oscillation in the thermoelectric power. (3) We measured the field dependence of the Hall effect, thermoelectric power and thermal conductivity on the two typical granular alloy system Co-Ag and Co-Cu, and found all the properties exhibit the field dependence correlated with the giant MR effect. We inferred that the basic mechanism of the giant MR effect in the granular alloys is same as that in multilayrs. (4) We have investigated the field dependence of various transport properties on UNiGa which shows a large MR effect to be discussed in relation to the magnetic multilayrs. We also found the large magnetic field effect in all the measured properties. From the Hall effect and thermoelectric power, we judged that the Fermi surface changes in the spin reorientation transition.