  We show that both the energy stored and dissipated by a system with
hysteretic nonlinearity in an applied field varies with the relative phase of
the sinusoidal components of the field, even if the magnitude of these
components, and thus an effective value of the field, are kept constant. The
explored system is a type-II superconductor in the critical state subjected to
a time varying applied magnetic field. Complete analytical expressions for
hysteresis loops, determined from basic physical phenomena, are known for this
system. A theoretically predicted variation in the energy is in good agreement
with our experimental measurements.
