Magnetic and dielectric behavior in YMn1-xFexO3 (x less than or equal to 0.5)

TL;DR

This study investigates how Fe doping affects the structural, magnetic, and dielectric properties of YMnO3, revealing phase transitions, spin reorientation, and magnetoelectric coupling variations with doping levels.

Contribution

It provides new insights into the structural phase change and magnetic behavior in Fe-doped YMnO3, highlighting the correlation between magnetic and dielectric properties.

Findings

Structural transition from hexagonal to orthorhombic phase at x > 0.2

Magnetic structure varies with Fe doping and temperature

Dielectric constant correlates with magnetic moment and shows magnetoelectric coupling

Abstract

The role of doping Fe on the structural, magnetic and dielectric properties of frustrated antiferromagnet YMn1-xFexO3 (x less than or equal to 0.5) has been investigated. The neutron diffraction analysis shows that the structure of these polycrystalline samples changes from hexagonal phase (space group P63cm) to orthorhombic phase (space group Pnma) for x > 0.2. The frustration parameter decreases with Fe substitution. All the compounds are antiferromagnetic and the magnetic structure is described as a mixture of {\Gamma}3 and {\Gamma}4 irreducible representation (IR) in the hexagonal phase and the ratio of these two IRs is found to vary with Fe doping (x less than or equal to 0.2). A continuous spin reorientation as a function of temperature is observed in these samples. The magnetic ground state in the orthorhombic phase of the higher doped samples (x greater than or equal to 0.3) is explained by taking {\Gamma}1 (GxCyAz) representation of Pnma setting. In YMnO3 suppression of dielectric constant {\epsilon} is observed below Tn indicative of magnetoelectric coupling. This anomalous behavior reduces in Fe doped samples. The dielectric constant is found to be correlated with the magnetic moment (M) obtained from neutron diffraction experiments and follows a M^2 behavior close to Tn in agreement with Landau theory.