Low temperature synthesis, magnetic and magnetotransport properties of (La1-xLux)0.67Ca0.33MnO3 (0 < x < 0.12) system

TL;DR

This study successfully synthesized Lu-substituted La0.67Ca0.33MnO3 using an auto-combustion method, revealing how Lu doping affects magnetic transition temperatures, magnetization, and magnetoresistance properties.

Contribution

It introduces a novel synthesis method for Lu-doped LCMO and systematically investigates its magnetic and transport properties, comparing them with other rare-earth substitutions.

Findings

All compounds exhibit ferromagnetic metal to paramagnetic insulator transition.

Transition temperatures and magnetization decrease with increasing Lu concentration.

Samples show high magnetoresistance, including about 30% low field magnetoresistance at less than 5 kOe.

Abstract

We have been able to synthesize Lu+3 substituted La0.67Ca0.33MnO3 (LCMO) by an auto-combustion method. Synthesis of this compound is not successful by conventional ceramic or other chemical methods. Magnetic and electrical transport properties of the Lu substituted LCMO [(La1-xLux)0.67Ca0.33MnO3 (0 < x < 0.12)] system have been investigated and compared with those of the Y+3, Pr+3, Dy+3 and Tb+3 substituted LCMO systems. All the compounds show a ferromagnetic metal to paramagnetic insulator transition at TC. The tolerance factor reduces from 0.917 for x = 0 to 0.909 for x = 0.12 and for this range all are ferromagnetic metals indicating the dominance of the coupling between spins due to double exchange over the antiferromagnetic superexchange interaction. The transition temperatures and magnetization decrease as the Lu concentration increases. This is satisfactorily accounted for on the basis of transition from ferromagnetic at x = 0 to canted spin order for x > 0. All the samples show higher magnitude of MR compared to that in pure LCMO at 80 kOe field in the temperature range of 5 to 320K. A fairly high value of low field magnetoresistance (LFMR) of about 30% is obtained in all the samples at a field less than 5 kOe.