Structural, magnetic and transport properties in the Pr-doped manganites La0.9-xPrxTe0.1MnO3

TL;DR

This study investigates how Pr-doping affects the structural, magnetic, and transport properties of La0.9-xPrxTe0.1MnO3 manganites, revealing phase transitions, changes in Curie temperature, and insulator-metal transitions related to bond and bandwidth modifications.

Contribution

It provides new insights into the effects of Pr-doping on structural symmetry, magnetic transition temperatures, and electronic transport in electron-doped manganites.

Findings

Structural transition from rhombohedral to orthorhombic with Pr-doping

Decreased Curie temperature and broader magnetic transition

Observation of insulator-metal transition at specific doping levels

Abstract

The effect of Pr-doping on structural, magnetic and transport properties in electron-doped manganites La0.9-xPrxTe0.1MnO3 with fixed carrier concentration are investigated. The room temperature structural transition from rhombohedral (R3C) to orthorhombic (Pbnm) symmetry is found in the samples with by the Rietveld refinement of x-ray powder diffraction patterns. The Curie temperature of samples decreases and the transition becomes broader with increasing Pr-doping level. For the samples with, there exist insulator-metal (I-M) transition. And the low-temperature I-M transition is observed at about 66K for the sample with x = 0.36, which may be related to the opening of a new percolation channel. For the samples with, r(T) curves display the semiconducting behavior (d\rho/dT < 0) in both high-temperature PM phase and low-temperature FM phase. The results are discussed in terms of the increased bending of the Mn-O-Mn bond with decreasing the average ionic radius of the A-site element <r_A> and the tolerance factor, resulting in the narrowing of the bandwidth, the decrease of the mobility of electrons and the weakening of DE interaction caused by the substitution of smaller Pr3+ ions for larger La3+ ion.