The effect of manganese doping and calcination temperature on polarization, structural and magnetic properties of multiferroic LuFe(1-)Mn O3 system

A systematic investigation of multiferroic LuFe (1- x ) Mn x O 3, prepared by ethylene glycol based sol-gel route, is presented. The effect of Mn content and calcination temperature is investigated employing XRD , Raman spectroscopy , XPS , SEM , and magnetometry measurements. Theoretical estimation of the polarization of the hexagonal unit cell is also explored. The obtained data reveals two crystallographic phases, orthorhombic Pnma , and hexagonal P6 3 cm . A mixture of the aforementioned phases is obtained when 0.3 ≥ x , at higher content a single phase hexagonal compound is formed. Rietveld refinement reveals distortion of the lattice as the a- unit cell parameter increases together with Mn content while the c- parameter decreases. The increase of calcination temperature from 1100 to 1300 °C, causes particle size to increase by a factor of around 5. XPS data shows that 1100 °C temperature is favorable for the iron in the 2+ state, while the formation of Mn 4+ is favored at 1300 °C. An increase in Mn content leads to a decrease of the Néel ordering temperature T N from ∼130 K at x = 0.2 to around ∼115 K when x = 0.4. Lastly, theoretical calculations reveal that the introduction of Mn into the unit cell almost linearly increases the polarization value. • Clarification of room temperature phase coexistence in LuFe (1- x ) Mn x O 3 system. • Insights into the non-uniform P6 3 cm unit cell distortion based on Mn doping. • Influence of Mn content and calcination temperatures on magnetic properties. • Theoretical calculations indicate about expected increase in polarization values upon Mn doping.