Effect of Substitution of Magnetic Metal Ions on Magnetic and Magnetoresistance Properties in LaSr2Mn2O7
The layered manganese oxides LaSr2Mn2-xTxO7 (T=Fe, Cr and Ni) has been prepared. The effect of substitution of transition metal ions for Mn on magnetic and magtoresistance properties has been studied. The compound has a tetragonal symmetry and the lattice parameters a decreases with increasing the doped content but the parameter c increases with x. It indicates that the MnO6 octahedron increase the distortion with x content. With the x increase, their ferromagnetic property was depressed. The Neel temperature TN was depressed gradually from 138K to 89K, 95K and 85K at x=0.3 for T=Fe, Ni and Cr respectively. Their magnetoresistance MR is gradually enhanced for all doped system. It suggests that the introduce of disorder in B-site have an important effect on the magnetic exchange and magnetoresistance because of the weaken of the double-exchange (DE) interaction.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
J. Feng et al., "Effect of Substitution of Magnetic Metal Ions on Magnetic and Magnetoresistance Properties in LaSr2Mn2O7", Materials Science Forum, Vols. 475-479, pp. 2227-2230, 2005