We present a theoretical analysis of the magnetocaloric effect in the
frustrated antiferromagnet \Eu. Monte Carlo simulations indicate a large
magnetic entropy change ΔSMmax∼5.14 J kg−1K−1
at T=2.45K for a moderate change in the external magnetic field ΔB=1.2 Tesla. The highest value of ΔSM seems to be associated with the
presence of a multicritical point in the magnetic field versus temperature
phase diagram (at Bm∼1.2 Tesla and Tm∼2.2 K) but it persists with
similar large values for a broad range of temperatures T≲Tm. Single
crystal \Eu~magnetization vs magnetic field experiments allowed us to obtain
the magnetocaloric effect for T>2 K. The results are consistent with the
theoretical analysis and show a large magnetocaloric effect for T∼2.5 K.
Finally, we present a phenomenological Landau functional analysis that provides
a simplified description of the phase diagram and of the magnetocaloric effect.
Although the magnetic frustration in this system leads to a rich phase diagram,
we found no clear indication that it plays a significant role enhancing the
magneticaloric effect, other than by reducing the transition temperatures and
fields.Comment: 10 pages, 10 figure