Magnetoresistance oscillations in double ferromagnetic tunnel junctions with layered ferromagnetic nanoparticles

Abstract

Tunnel magnetoresistance in double tunnel junctions with layered ferromagnetic nanoparticles was investigated. The sample comprises two ferromagnetic electrodes (CoFe/Fe) separated by an Al/sub 2/O/sub 3/ insulating layer in which layered Co/sub 80/Pt/sub 20/ nanoparticles are embedded. The nanoparticles are ellipsoidal with an average diameter of 3.7 nm, and composes a well-defined layer. At 10 K, we observed magnetoresistance oscillation with respect to the bias voltage. The observed TMR oscillation, with a period of 1.6 mV, accompanied oscillations of the conductance. We consider that the conductance oscillation may originate from the single electron charging effect.