Magnetocaloric properties of La0.7Ca0.3Mn16O3 and La0.7Ca0.3Mn18O3 manganites and their “sandwich”

The effect of 16О → 18О isotope substitution on specific heat and magnetocaloric effect of polycrystalline La0.7Ca0.3MnO3 manganite is studied. Mainly the effect of isotope substitution for the specific heat and magnetocaloric effect is only the reduction of temperatures of anomalies. ΔTad values at magnetic field change ΔH = 18 kOe are equal to ΔTad = 2.41 K and 2.60 K for La0.7Ca0.3Mn16O3 (LCMO16) and La0.7Ca0.3Mn18O3 (LCMO18), respectively. The sandwich of the LCMO16 and LCMO18 samples was produced for direct measurement of ΔTad. The use of sandwich from materials with near similar magnetocaloric properties increases the relative cooling power by about 20%.