Specific heat and magnetocaloric effect in Pr0.6Sr0.4−xAgxMnO3 manganites

The detailed investigation on the specific heat in manganites of Pr0.6Sr0.4−xAgxMnO3 (x = 0.05 and x = 0.1) has been reported. The experimental conditions were: the temperature range 1.8-330 K and applied magnetic fields of 0, 1, 2 and 3 T. Specific heat results confirmed two phase transitions, a structural one at Tstr = 43 K for both samples and a paramagnetic-ferromagnetic one near TPM-FM = 288 K and 284 K for the x = 0.05 and x = 0.1 sample, respectively. For the more doped sample the magnetic field causes the shift of the PM-FM transition temperature towards higher temperatures. A thorough analysis of particular contributions to the specific heat was presented. The indirect magnetocaloric effect was deduced for the more doped sample (x = 0.1). Under an applied magnetic field of 3 T magnetic entropy changes and adiabatic temperature exhibits a maximum. The absolute ΔSmax reaches the value of 1.74 J/mol K, resulting in adiabatic cooling of ΔTad = 0.95 K. Such result confirms presented samples as promising candidates for the magnetic cooling technology at room temperature.