Order by quenched disorder in the model triangular antiferromagnet RbFe(MoO4)2

Abstract

We observe a disappearance of the 1/3 magnetization plateau and a striking change of the magnetic configuration under a moderate doping of the model triangular antiferromagnet RbFe(MoO4)2. The reason is an effective lifting of degeneracy of mean-field ground states by a random potential of impurities, which compensates, in the low temperature limit, the fluctuation contribution to free energy. These results provide a direct experimental confirmation of the fluctuation origin of the ground state in a real frustrated system. The change of the ground state to a least collinear configuration reveals an effective positive biquadratic exchange provided by the structural disorder. On heating, doped samples regain the structure of a pure compound thus allowing for an investigation of the remarkable competition between thermal and structural disorder.

arXiv commentLetter and Supplemental material, 10 pages, 14 figures, accepted for Phys.Rev.Letters, July 2017: https://journals.aps.org/prl/accepted/9907fY9bP6c12565988d7b717d5069faa7fb6863a

References in corpus (12)

• Experimental Realization of Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet
• Half-magnetization plateau stabilized by structural distortion in the antiferromagnetic Heisenberg model on a pyrochlore lattice
• Direct transition from a disordered to a multiferroic phase on a triangular lattice
• Quasi two-dimensional antiferromagnet on a triangular lattice RbFe(MoO4)2
• Successive phase transitions and phase diagrams of the quasi-two-dimensional triangular antiferromagnet Rb4Mn(MoO4)3
• Magnetic phase diagram, critical behaviour and 2D-3D crossover in a triangular lattice antiferromagnet RbFe(MoO4)2
• Triangular antiferromagnet with nonmagnetic impurities
• Multiferroicity in the generic easy-plane triangular lattice antiferromagnet RbFe(MoO4)2
• Magnetic excitations in multiferroic LuMnO3 studied by inelastic neutron scattering
• Co-existing chiral and collinear phases in a distorted triangular antiferromagnet
• Real-space perturbation theory for frustrated magnets: application to magnetization plateaus
• Collective impurity effects in the Heisenberg triangular antiferromagnet

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