Isostructural changes in h-YMnO3 by Fe-substitution: effects on multiferroicity

Abstract: Iron-substitution in hexagonal YMnO3 causes isostructural intra-lattice changes exceeding those of the lattice cell, contrary to the effects of non-magnetic B-site dopants. Magnetization M(T) evidence antiferromagnetic (AFM) ordering of the specimens with little weak ferromagnetism, and the metrices of exchange interaction suppress with Fe-doping, attributed to the lengthening of the Mn-O planar bond lengths. Ferroelectric (FE) P-E hysteresis loops reflect subdued and conductive ferroelectricity with increased Fe-substitution, traced to the reduced polyhedral buckling. Dielectric {\epsilon}'(T) results showing highly doping-dependent anomaly at the N\'eel temperature signify strong magnetostrictive tunability and imply linear magneto-electric (ME) coupling. We recognize a correspondence of the structure-property changes versus Fe-doping, with the reported magnetostrictive effects upon cooling below TN. Correlations of AFM-FE-ME properties with their relevant microstructural attributes underline the spin-lattice-dipole coupling and provide significant characteristic figures.