Structural and electromagnetic characterizations of Fe–SrF₂granular films

Abstract

Abstract.We investigate composite Fe-SrF 2 films to explore new materials showing the granular type tunneling magnetoresistance (TMR) effect. The films are composed of Fe nano-particles embedded in a SrF 2 matrix. The electromagnetic properties of the ferromagnetic metal-insulator films are confirmed, including super-paramagnetism, tunnel conduction, and TMR. We obtain a TMR of 3% at RT and 5% at 77 K. The film resistivity is much higher than that of oxide-based granular film. We also fabricate the nanostructures of granular films and aim at the application of the single-electron transistor. As a result, we observed Coulomb blockade (CB) region and CB oscillation at low temperature.

Tunnel current measurement of MgO and MgO/Fe/MgO nanoregions during TEM observation

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