Tang Y.,Anhui Key Laboratory of Spin Electronic and Nanomaterials Cultivating Base |
Tang Y.,Suzhou University |
Wang G.,Anhui Key Laboratory of Spin Electronic and Nanomaterials Cultivating Base |
Wang G.,Suzhou University |
And 6 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2011
The polycrystalline samples of La1-xNaxMnO3(x=0.05, 0.15, 0.33) were prepared by solid-state reaction. Influence of substituting La3+ with Na+ at A-site on magnetic and electric properties was studied through XRD(X ray diffraction), R-T(resistance-temperature) curves, M-T(magnetization-temperature) curves and ESR(electron spin resonance) curves. The results showed that: all samples exhibited a paramagnetic-ferromagnetic transition associated with metal-insulator one whereas the values of resistance decreased firstly and then increased, but magnetizations increased firstly and then decreased with the substituting concentration increasing. But the Curie temperatures of the samples increased monotonically with the substituting concentration increasing. Near the Curie temperature, paramagnetic phase and ferromagnetic phase coexisted, which implied that phase separation existed in the system. When x=0.05, antiferromagnetic phase and ferromagnetic phase coexisted, and an intrinsic spin-glass formed in the system at low temperature. Spin-glass behavior was destroyed with the increasing of Na content. The change of the magneto-electric properties originated from the changes of the crystal lattice structure and tolerance factor as well as the change of Mn3+ /Mn4+ ratio. Source