The impact of Bi substitution at the Mn-site on the structural, magnetic, and magnetocaloric characteristics of La0.65Ca0.20Pb0.15Mn1−xBixO3 (x = 0.0, 0.01, 0.03, and 0.05) perovskites has been systematically examined. X-ray diffraction (XRD) results confirmed that all samples were found to crystallize in a rhombohedral crystal structure with space group \(R\overline{3 }c\) . Thermomagnetic measurements revealed a progressive reduction in the Curie temperature (TC) with increasing Bi concentration, decreasing from 322 K for the parent phase to 289 K for the highest doping level, shifting the magnetic transition closer to room temperature, which is desirable for practical refrigeration applications. Conversely, the magnetic entropy change (− ΔSM) exhibited a steady enhancement, increasing from 4.18 Jkg−1 K−1 at x = 0.0 to 5.06 Jkg−1 K−1 at x = 0.05 under a field change of 5 T. The relative cooling power (RCP) exhibited a non-monotonic dependence on doping, with the maximum value of 245.78 Jkg−1 obtained for the parent sample, suggesting an optimal balance between entropy change and transition width. Arrott plot analysis confirmed that all compositions undergo a second-order magnetic transition. These results indicate that Bi doping is an efficient strategy to lower TC toward room temperature while simultaneously enhancing the magnetocaloric effect, highlighting the potential of these compounds for magnetic refrigeration (MR) near room temperature.
