  An improved micro-SQUID technique is presented allowing us to measure the
temperature dependence of the magnetisation switching fields of single
nanoparticles well above the critical superconducting temperature of the SQUID.
Our first measurements on 3 nm cobalt nanoparticle embedded in a niobium matrix
are compared to the Neel Brown model describing the magnetisation reversal by
thermal activation over a single anisotropy barrier.
