Magnetic and dielectric behavior in YMn1-xFexO3 (x ≤ 0.5)

The role of doping Fe on the structural, magnetic, and dielectric properties of frustrated antiferromagnet YMn1-xFexO3 (x <= 0.5) has been investigated. The neutron diffraction analysis shows that the structure of these polycrystalline samples changes from hexagonal phase (space group P6(3)cm) 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 <= 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 >= 0.3) is explained by taking Gamma 1 (G(x)C(y)A(z)) 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 T-N in agreement with Landau theory. (C) 2014 AIP Publishing LLC.