Hideo Kaiju
Hokkaido University, Japan
Title: Nanoscale junctions utilizing magnetic thin-film edges
Biography
Biography: Hideo Kaiju
Abstract
Recently, we have proposed a new method for the fabrication of nanoscale junctions utilizing thin-film edges. In this method, the edges of two metal thin films are crossed, and molecules, metal-oxide, etc. are sandwiched between their two edges. The junction area is determined by the film thickness, in other words 10 nm thick films could produce 10×10 nm2 nanoscale junctions. This method offers a way to overcome the feature size limit of conventional optical lithography. Moreover, novel spintronics devices, such as large magnetoresistance devices and spin-filter devices, could be created when magnetic materials are used as metal thin films. In this presentation, we report the detail fabrication technique for nanoscale junctions and discuss the structural and electrical characteristics in various nanoscale junctions. The results include the observation of ohmic characteristics in Ni/Ni devices, nanoscale tunneling phenomena in Ni/NiO/Ni devices, and the ballistic regime of nanoscale molecules in Ni/P3HT:PCBM/Ni devices. Moreover, we report ongoing spintronics devices utilizing stray magnetic fields as a new type of spin-filter device. This device consists of inorganic complexes or quantum dots (QDs) sandwiched between two crossed edges of magnetic thin films. In this structure, a high magnetic field could be locally generated in the inorganic complexes or QDs due to the contributions of the stray field from both edges of the magnetic thin films. Since a large magnetic field produces a large Zeeman effect, energy splitting of the inorganic complexes or QDs can be enhanced. Therefore, a large spin-filter effect can be expected. In this talk, we will focus on the structural and magnetic properties in our proposed nanoscale spintronics devices.
