Effect of Strontium substitution on the structural and magnetic properties of La1.8Sr0.2MMnO6 (M = Ni, Co) layered manganites

TL;DR

This study investigates how strontium substitution affects the structural and magnetic properties of layered manganites La1.8Sr0.2MMnO6 (M = Ni, Co), revealing significant changes in grain size, phase purity, and magnetic transition temperatures.

Contribution

It provides a systematic analysis of morphological, structural, and magnetic changes due to Sr substitution in La2NiMnO6 and La2CoMnO6 manganites, highlighting differences in transition temperatures.

Findings

Grain sizes are significantly reduced with Sr substitution.

Sr substitution shifts ferromagnetic to paramagnetic transition temperatures.

XPS confirms phase purity and oxygen vacancy presence.

Abstract

Sr substituted perovskites La1.8Sr0.2MMnO6 (M = Ni, Co) were synthesized using solid state reaction technique to present a systematic study on their morphological, structural and magnetic properties. The average grain size of the as-prepared La1.8Sr0.2NiMnO6 samples are in the range of 0.2-0.7 {\mu}m and those for La1.8Sr0.2CoMnO6 manganites are 0.1-2.8 {\mu}m, which is significantly less than that of unsubstituted La2NiMnO6 (LNMO) and La2CoMnO6 (LCMO) manganites. The XPS analysis enlightened about phase purity, binding energy and oxygen vacancy of La1.8Sr0.2MMnO6 manganites. The Sr substituted LNMO has revealed a sharp ferromagnetic to paramagnetic phase transition at 160 K which is about 120 K less than that of parent LNMO. The Sr substituted LCMO exhibited such a transition at 220 K which is 8 K less than that of parent LCMO. The temperature dependent magnetization measurements suggest that the effect of Sr on the transition temperature in LNMO is more significant than that of LCMO.