  The magnetic and magnetocaloric properties of polycrystalline
La0.70(Ca0.30-xSrx)MnO3:Ag 10% manganite have been investigated. All the
compositions are crystallized in single phase orthorhombic Pbnm space group.
Both, the Insulator-Metal transition temperature (TIM) and Curie temperature
(Tc) are observed at 298 K for x = 0.10 composition. Though both TIM and Tc are
nearly unchanged with Ag addition, the MR is slightly improved. The MR at 300 K
is found to be as large as 31% with magnetic field change of 1Tesla, whereas it
reaches up to 49% at magnetic field of 3Tesla for La0.70Ca0.20Sr0.10MnO3:Ag0.10
sample. The maximum entropy change (\DeltaSMmax) is 7.6 J.Kg-1.K-1 upon the
magnetic field change of 5Tesla, near its Tc (300.5 K). The
La0.70Ca0.20Sr0.10MnO3:Ag0.10 sample having good MR (31%1Tesla, 49%3Tesla) and
reasonable change in magnetic entropy (7.6 J.Kg-1.K-1, 5 Tesla) at 300 K can be
a potential magnetic refrigerant material at ambient temperatures.
