Magnetocaloric effect in La1−xKxMnO3 (x = 0.11, 0.13, 0.15) composite structures in magnetic fields up to 80 kOe

Magnetocaloric properties of La1−xKxMnO3 (x = 0.11, 0.13, 0.15) manganites and their two and three layer composite structures are measured under low and high magnetic fields by the direct method. The relative cooling power (RCP) in composites is revealed to increase by 20-40% in moderate magnetic fields of 20 kOe compared with parent materials. The value of the magnetic field, at which the greatest increase in RCP of the composite takes place, depends on the proximity of Curie temperatures of the materials composing the structure; for the studied materials a maximum increase in the RCP is observed in the magnetic field range from 40 to 50 kOe.