Interplay between ferromagnetism and charging effects in the transport through nanoparticle arrays

Transport through a metallic nanoparticle is governed by Coulomb
blockade physics. Due to the discrete character of the charge the
current is suppressed up to a finite threshold voltage. The current is a
strongly non-linear function of bias voltage, which includes a staircase
behavior under certain circumstances. When the nanoparticle is placed in
between two ferromagnetic electrodes the interplay of ferromagnetism and
discrete charging leads to new phenomena. If the nanoparticle is
metallic and the spin relaxation time in it is long, a spin dependent
potential in the nanoparticle, the so-called spin accumulation, can
appear. Charging effects are strongly enhanced in nanoparticle arrays .
In this talk, after an introduction to Coulomb blockade physics and
spin accumulation I will show that the interplay between ferromagnetism
and charging effects has a very strong effect in the transport
properties of nanoparticle arrays, resulting in very unusual
current-voltage and magnetoresistance curves.