Tang Nujiang

Magnetic and Transport Properties of oxygen-Deficient Perovskite Manganites

Effects of oxygen deficiency on the magnetic and transport properties of La2/3Ba1/3MnO3-δ polycrystalline perovskites have been investigated. As the nonstoichiometry parameter δ increases from 0.00 to 0.10, the lattice parameters at room temperature increase from 3.892(3) A to 3.909(3) A, the resistivity increases and the ferromagnetic ordering transition temperature shifts from 337 K to 268 K. A large magnetoresistance effect with -Δρ/ρ0 of about 30% (955 kA/m, δ = 0.10) and a large magnetic entropy change of about 2.7 J/kgK (796 kA/m, δ = 0.00) is obtained in polycrystalline La2/3Ba1/3MnO3-δ. The enhanced magnetoresistance effect at low temperature would be related to the grain boundaries of the polycrystalline samples.