Experimental Realization of a Unique Class of Compounds: XY-Antiferromagnetic Triangular Lattices, KAg2Fe[VO4]2 and RbAg2Fe[VO4]2, with Ferroelectric Ground States
journal contributionposted on 28.10.2014, 00:00 by Ngozi E. Amuneke, Joshua Tapp, Clarina R. de la Cruz, Angela Möller
AAg2Fe[VO4]2 with A = K or Rb was synthesized by solid state methods and characterized by thermodynamic properties measurements (Néel order at TN ≈ 3.0 K). The respective nuclear (aK,Rb = 5.48 Å, cK = 7.212 Å, cRb = 7.357 Å, P3̅, Z = 1) and magnetic structures were refined using neutron diffraction in applied magnetic fields. The results indicate enhanced structural stability of the P3̅ structure and the realization of a frustrated triangular lattice with antiferromagnetic XY-anisotropies. Two magnetic structures were identified: a helical and chiral Y-phase with a propagation vector of (1/3, 1/3, ≈ 0.39) and a commensurate up–up–down phase. These unique compounds offer convenient experimental access for optimizing the features and properties of ferroaxial multiferroic materials.