Magnetic and transport properties of Dy substituted layered perovskite La1.3Sr1.7Mn2O7

The effect of Dy substitution for La site in layered manganese oxides La1.3-xDyxSr1.7Mn2O7 on the magnetic and electrical properties has been investigated. With the La3＋ substituting by Dy^3＋, 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 Dy^3＋. Addtionally, the small Dy^3＋ 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 Lal.3Sr1.7Mn2O7, so there is only one insulator-metal transition in the ρ-T curve of the sample with x = 0.05 and x = 0.1.