Magnetic and Magnetotransport Properties in Nanogranular Co/C<SUB>60</SUB>-Co Film with High Magnetoresistance

Abstract

Magnetic properties were investigated for the alternately deposited film of C60 and Co which has found to exhibit tunnel magnetoresistance (MR) of 10–80%. Magnetic field and temperature dependences of magnetization showed typical superparamagnetic behaviors with the blocking temperature of 40 K. The magnetization curve at 300 K was well fitted by the Langevin function with the size distribution of Co particles, and the mean diameter and size distribution were evaluated to be 3.1 nm and ∼1 nm, respectively. Based on the magnetic properties, the structure and magnetotransport properties are discussed in details.