  It is shown that the phase shift between an applied weak alternating magnetic
field and the magnetocaloric response signal of the magnetic material is
drastically sensitive to the order of phase transition. Namely, at the
second-order phase transition, the phase shift does not depend on the magnetic
field magnitude, while in the first-order phase transition this one depends
significantly on the field strength. We have shown that this effect follows
from the general critical dynamics theory.
