Magnetocaloric properties of transition metal doped Sr₂FeMo_0.9B_0.1O₆ (B = Mo, Nb, V, W) double perovskites

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<P><B>Abstract</B></P> <P>Double perovskite Sr<SUB>2</SUB>FeMo<SUB>0.9</SUB>B<SUB>0.1</SUB>O<SUB>6</SUB> materials doped with fixed amount of various transition metals (B = Mo, Nb, V, W) were synthesized using the solid state reaction method and investigated for their magnetic and magnetocaloric performance. X-ray diffraction profiles of the samples established tetragonal crystal structure with I4/mmm space group in these materials. A strong variation in the magnetization and Curie temperature values was observed in these samples as a result of transition-metal doping. The magnetization measurements and Arrott plots revealed a second order nature of magnetic phase transition in the investigated samples. The magnetocaloric effects in terms of the magnetic entropy change and relative cooling power (RCP) were calculated from the isothermal magnetization curves of the samples. The V-doped sample among the entire batch exhibited a maximum magnetic entropy change of 0.55 J/kg K with an RCP value of 60 J/kg at an applied magnetic field of 2.5 T. The tunability of magnetization, Curie temperature and magnetocaloric features in these materials at low applied field make them very attractive for use in solid state magnetic refrigeration technology.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Investigation of the structural, magnetic and magnetocaloric properties of different transition metals doped Sr<SUB>2</SUB>FeMoO<SUB>6</SUB>. </LI> <LI> Increased magnetization and magnetocaloric properties with transition metal doping. </LI> <LI> Tuning of the magnetization, Curie temperature and magnetocaloric properties with controlled transition metal doping. </LI> <LI> Second order of ferromagnetic phase transition with soft ferromagnetic properties. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Magnetization as a function of temperature in the Sr<SUB>2</SUB>FeMo<SUB>0.9</SUB>B<SUB>0.1</SUB>O<SUB>6</SUB> samples with B = (Mo, Nb, V, W).</P> <P>[DISPLAY OMISSION]</P>