Room Temperature Magnetocaloric Effect in <tex> ${\hbox{La}}_{0.7}{\hbox{Sr}}_{0.3}{\hbox{Mn}}_{1\hbox{-}{\rm x}}{\hbox{Co}}_{\rm x}{\hbox{O}}_{3}$</tex>

다국어 초록 (Multilingual Abstract)

<P>We have investigated the magnetic properties and magnetocaloric effect in La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB> prepared by a conventional solid-state reaction method. Magnetic measurements versus temperature revealed that the Curie temperature (T<SUB>C</SUB>) decreased gradually with increasing Co content (x); T<SUB>C</SUB> values are about 360, 310, 296 and 280 K for x =0.0, 0.06, 0.08 and 0.1, respectively. Magnetic entropy change (ΔS<SUB>m</SUB>) of the samples under a magnetic field change of 10 kOe was calculated by using isothermal magnetization data. We have found its maximum (|ΔS<SUB>max</SUB>|) achieved around T<SUB>C</SUB>, which is not changed much (~ 1.5 J·kg<SUP>-1</SUP>·K<SUP>-1</SUP>) with increasing Co-doping concentration. If combining the samples with x = 0.06, 0.08 and 0.10 for magnetic refrigeration, particularly, the temperature range can be used in between 266 K and 322 K, where |ΔS<SUB>max</SUB>| values are stable at about 0.98 J·kg<SUP>-1</SUP>·K<SUP>-1</SUP>. The relative cooling power is accordingly about 55 J·kg<SUP>-1</SUP> and comparable to that of other magnetocaloric alloys. These results suggest La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB> compounds to be a potential candidate for magnetic refrigerators at room temperature.</P>