  We report the results of our investigations on the influence of partial
substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties
of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic
susceptibility and heat capacity data, apart from confirming the occurrence of
magnetic transitions at ~ 121 and 13 K in DyFe0.5Cr0.5O3, bring out that the
lower transition temperature only is suppressed by rare-earth substitution.
Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln= Er and
Gd). There is an evidence for magnetoelectric coupling in all these materials
with qualitative differences in its behavior as the temperature is changed
across these two transitions. Remnant electric polarization is observed for all
the compounds. The most notable observation is that electric polarization is
seen to get enhanced as a result of rare-earth substitution with respect to
that in DyFe0.5Cr0.5O3. Interestingly, similar trend is seen in magnetocaloric
effect, consistent with the existence of magnetoelectric coupling. The results
thus provide evidence for the tuning of magnetoelectric coupling by rare-earth
substitution in this family of oxides.
