Electron-lattice coupling and double exchange effects to improve TCR of La0.67-xNdxCa0.25Sr0.08MnO3 films grown on La0.3Sr0.7Al0.65Ta0.35O3 substrates

In this study, La 0.67− x Nd x Ca 0.25 Sr 0.08 MnO 3 (LNCSMO, x  = 0.09, 0.10, 0.11, 0.12) films were prepared by sol-gel spin coating method. The results indicate that the LNCSMO film is oriented and grown on a La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 (LSATO) (00 l ) substrate. In addition, with the increase of Nd 3+ content, the Mn-O bond length ( d Mn-O ) and Mn-O-Mn bond angle ( θ Mn-O-Mn ) decreases. The concentration ratio of Mn 4+ increases firstly and then decreases, and resulting in an enhanced and then weakened double exchange (DE) effect. Measuring the variation of sample resistivity with temperature ( ρ -T) using the standard four-probe method. As the content of Nd 3+ increases, the metal-insulator transition temperature ( T p ) gradually decreases, and the resistivity ( ρ ) gradually increases. The replacement of Nd 3+ makes the peak temperature coefficient of resistivity value ( TCR max ) of the material firstly increase and then decrease. At x  = 0.11, the TCR max reaches 34.28 % K −1 at 254.72 K. This provides new insights into the impact of Nd doping on electrical transport properties.