Effect of cation size and size-disorder on the magnetic and electron transport properties of La(0.7-x)Ln(x)Sr(0.3)MnO(3) (Ln = Gd and Dy)

Abstract

Magnetic and electron transport properties of La0.7−xLnxSr0.3MnO3 with Ln=Gd and Dy have been investigated over a wide range of compositions to explore the effects of the radius of the A-site cation, 〈rA〉, and the size-disorder as measured by σ2. These manganates exhibit ferromagnetism and insulator–metal transitions up to a critical value of x (xc), with the Tc (TIM) values decreasing with 〈rA〉. When x ≥ xc, however, the manganates cease to be ferromagnetic and instead they show an abrupt decrease in magnetization and increase in resistivity, suggesting the likely occurrence of electronic phase separation.