Fe, Co/MgF_2多層膜の電気伝導  [in Japanese] Magnetoresistance of Fe,Co/MgF_2 Multilayered Thin Films  [in Japanese]

Fe/MgF_2 and Co/MgF_2 multilayers were prepared by alternate deposition in order to investigate their electric transport properties. The resistivity of the multilayers changes from metallic to semiconductive when the metal layer thickness is decreased to 45 Å for Fe and 40 Å for Co with a 30 Å MgF_2 layer thickness. For films with semiconductor-like electronic conduction, the logarithm of resistivity varies as T^<-1/2>, which means that the tunneling process is dominant. A tunneling magnetoresistance of a few percent was found in the semiconductor-like films. The maximum MR at 15 kOe was found to be 8% for an (Fe 15 Å / MgF_2 20 Å) multilayer at room temperature.