  Novel thermal effects across the first order antiferromagnetic (AFM) -
ferromagnetic (FM) transition in an intermetallic alloy are reported. They show
instances of warming when heat is extracted from the sample, and cooling when
heat is provided to the sample across AFM-FM transition in Ta doped $HfFe_2$,
thus providing indisputable evidence of metastable supercooled AFM and
superheated FM states, respectively. Such thermal effects in a magnetic solid
prepared from commercially available materials has been reported for the first
time. The transition proceeds in multiple steps which is interpreted in the
framework of quenched disorder broadening of AFM-FM transition and classical
nucleation theory. Measurements in the presence of magnetic field conform to
above frame work.
