Impact of B -site doping on magnetic and magnetocaloric effect of Pr 0.75 Bi 0.05 Sr 0.1 Ba 0.1 Mn 1-x Ti x O 3 (0x0.04) manganites

Ceramic Pr0.75Bi0.05Sr0.1Ba0.1Mn1-xTixO3 (x = 0.0, 0.02 and 0.04) samples were prepared by the conventional sol-gel route. For a magnetic applied field of 0.05T, the magnetic measurements indicated that the ferromagnetic-paramagnetic (FM-PM) transition temperature TC decreased from 130 to 98 K with increasing titanium doping level from x = 0.0 to 0.04 respectively. The magnetic properties of these compounds are discussed relying on the magnetization measurements and the susceptibility analysis. The undoped compound displays a Griffiths phase at TG = 285 K which confirms the existence of ferromagnetic entities within the paramagnetic domain far above Tc. At μ0H = 5T, the maximum value of the magnetic entropy change varies from 2.33 to 1.88 J kg−1K−1 for x varying from 0.00 to 0.04 respectively. The master curve behavior for the temperature dependence of ΔSM(T), determined for various applied magnetic fields, revealed the second-order FM-PM phase transition of our compounds. Accordingly, important values of the relative cooling power (RCP) for all investigated materials were obtained proving that they can be proposed as good candidates for magnetic refrigeration at low temperatures. © 2020 Elsevier Masson SAS