MAGNETIC-RELAXATION IN SMALL-PARTICLE SYSTEMS - T IN(T TAU-0) SCALING/

Although most of the experimental work dealing with the magnetic relax ation of systems characterized by the existence of an energy-barrier d istribution have been analyzed in terms of the so-called logarithmic a pproximation, this is not a good approximation because obviously it ca nnot describe the behavior for the whole range of temperatures and tim es. An alternative method called T ln(t/tau0) scaling is proposed. Thi s scaling method allows one to extrapolate the relaxation behavior at times that are experimentally completely unaccessible. From this scali ng it is also possible to determine the attempt frequency 1/tau0, and if a certain distribution of energy barriers is assumed the width sigm a and the mean energy barrier is also obtained. The validity of the lo garithmic approximation is critically discussed.