Magnetoresistance Of Fe-srf_2 Single-electron Devices With A Current-in-plane Geometry

摘要

We fabricated single-electron tunnelling devices with the current-in-plane geometry, which were made of Fe-SrF_2 nanogranular films (33. vol%Fe, length: 50-5000 nm, width: 400 nm). Their electric properties such as the current-to-bias voltage curves as well as the tunnelling magnetoresistance (TMR) were investigated by the two terminal measurements. A clear Coulomb blockade (CB) regime was recognized at 8 K when the device length was less than 500 nm. At about the CB threshold voltage, the sign change of TMR ratio was observed while it was +3% (a value corresponding to the data of Fe-SrF_2 films in millimeter size) at higher voltage (e.g. 1 V).