Investigating the structure, magnetism, magnetocaloric effects and critical behavior of Eu(Ti,B)O3 perovskites

•Enhanced FM interactions and giant low-field MCEs are achieved in Eu(Ti,B)O3 compounds.•The peak values of −ΔS M are 15.2 and 27.4 J·kg−1·K−1 for μ0ΔH = 0–1 and 0–2 T, respectively.•Critical behavior analysis indicates a dominance of long-range FM interactions in EuTi0.75B0.25O3.•The considerable low-field MCEs make them promising magnetic refrigerants around liquid helium temperature. EuTiO3 exhibits various interesting physical properties, including magnetocaloric effect, quantum paraelectricity, magnetoelectricity, and multiferroic properties, thus attracting a broad range of attention from the researchers. The delicate balance between ferromagnetic coupling and antiferromagnetic interactions offers the feasibility of modulating the magnetic properties and magnetocaloric effect for this perovskite. Herein, a range of Eu(Ti,B)O3 perovskites were prepared by substituting titanium with different amounts of boron. A comprehensive investigation on their structure, magnetism, magnetocaloric effect, and critical behavior was performed. All the compounds are confirmed to be crystallized in a single cubic perovskite structure with space symmetry of Pm3m, with the introduced boron uniformly distributed in the compounds. The transition temperatures are determined to be 6.0, 6.5, 5.0, and 5.0 K for EuTi0.9375B0.0625O3, EuTi0.875B0.125O3, EuTi0.8125B0.1875O3, and EuTi0.75B0.25O3, respectively. The results of both magnetic measurements and critical behavior analysis suggest that appropriate substitution of boron promotes the magnetic transition from AFM to FM in Eu(Ti,B)O3. In addition, significantly enhanced low-field magnetocaloric effects were observed in these perovskites. Under field changes of 0–1 and 0–2 T, the values of -ΔSMmax are 14.7 and 26.4 J·kg−1·K−1 for EuTi0.8125B0.1875O3, 15.2 and 27.4 J·kg−1·K−1 for EuTi0.75B0.25O3, respectively.