Polycrystalline two-layered perovskite La2.5-xK0.5+xMn2O7+δ (0 < x < 0.5) samples have been prepared by a modified sol-gel method and their magnetoresistance and magnetocaloric effects have been studied. A large deviation between the metal-insulator (MI) transition temperature (Tρ) and the magnetic transition temperature (TC) is observed. Large magnetoresistance (MR) effects with Δρ/ρ0 of ∼40% at 12 kOe are obtained in wide temperature ranges. The maximum of the magnetic entropy change peaks at its Curie temperature (TC), far above its MI transition temperature (Tρ). The large magnetic entropy change (∼1.4 J/kg.K) is obtained in the sample La2.5-xK0.5+xMn2O7+δ (x = 0.35) upon 10 kOe applied magnetic field.
Scopus Subject Areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- 75.30.Sg Magnetocaloric effect, magnetic cooling
- 81.05.Mh Cermets, ceramic and refractory composites
- 82.80.-d Chemical analysis and related physical methods of analysis