Magnetic and transport properties of Dy substituted layered perovskite La_1.3Sr_1.7Mn₂O₇

The effect of Dy substitution for La site in layered manganese oxides La_1.3-xDy_xSr_1.7Mn₂O₇ on the magnetic and electrical properties has been investigated. With the La³⁺ substituting by Dy³⁺, the long range three-dimensional ferromagnetism transition and the insulator–metal transition disappear. These effects are attributed to the lattice distortion due to the substitution of the smaller Dy³⁺. Addtionally, the small Dy³⁺ is inclined to occupy the R site which is in the rock-salt layer, then the distribution of La, Sr, Dy ions in Dy-doped sample should be more orderly than that in La_1.3Sr_1.7Mn₂O₇, so there is only one insulator–metal transition in the \rho–T curve of the sample with x=0.05 and x=0.1.