Study of Structural, Electrical, and Magnetic Properties of Layered Perovskite Oxides LnSr2TiFeO7 (Ln = Nd, Gd)

Abstract

We report here the synthesis and results of electrical resistivity and magnetic susceptibility measurements in the low temperature range of the rare-earthdoped bilayered system LnSr 2 TiFeO 7 (Ln = Nd, Gd). Both phases crystallize with a tetragonal unit cell in space group I4/mmm. The phases exhibit insulating behavior, and the electrical transport mechanism agrees with the Mott variable-range hopping model. The decrease in electrical resistivity with decreasing ionic size of the rare-earth ion could be attributed to enhancement of the three-dimensional (3D) character along the c-axis because of the proximity of the (Ti/Fe)O 2 and (Ln,Sr)O layers along the c-axis. The magnetic studies suggest that the phases are antiferromagnetic and the antiferromagnetic behavior could be due to the Fe 3+ -O-Fe 3+ exchange interaction.