Hysteresis is one of the most widely recognized signatures of magnetically ordered materials.
It is a nonequilibrium, history dependent phenomenon, which ultimately originates from
metastability, that is, the existence of very many local minima in the free energy landscape
in configuration space. It is also a property of considerable interest from a technological
perspective, since virtually all applications of magnetism exploit hysteresis in some way.
In broad terms, the goal of the current research is to measure the field and temperature dependence
of the irreversible response of a wide spectrum of magnetic materials, including canonical
ferromagnets, sintered permanent magnetic, frustrated spin glasses, and froze suspensions of
nanodimensional particles, and to interpret these data withing the framework of a model which
decomposed the free energy into an ensemble of interacting, temperature dependent, two-level