Physical Sciences and Mathematics Commons^™

Superspin Glass Behaviour Of Interacting Ferromagnetic Nanoparticles In Discontinuous Magnetic Multilayers, Christian Binek

Christian Binek Publications

Discontinuous magnetic multilayers [Co80Fe20(t)/Al2O3(3nm)]10 with t = 0.9 and 1.0nm are studied by SQUID magnetometry and ac susceptibility. Owing to dipolar interaction the superparamagnetic cluster systems undergo collective glass-like freezing upon cooling. While both samples exhibit very similar glass temperatures Tg » 45 K and critical exponents zn » 10 and g » 1.4 as obtained from the temperature dependencies of the relaxation time, t, and the nonlinear susceptibility, c3, dynamical scaling reveals different critical exponents, b(0.9nm) »1.0 and b(1.0nm) » 0.6, respectively.