Abstract
The local atomic and magnetic structures of the compounds ( = Na, Cu), which realize a geometrically frustrated, spatially anisotropic triangular lattice of Mn spins, have been investigated by atomic and magnetic pair distribution function analysis of neutron total scattering data. Relief of frustration in is accompanied by a conventional cooperative symmetry-lowering lattice distortion driven by Néel order. In , however, the distortion has a short-range nature. A cooperative interaction between the locally broken symmetry and short-range magnetic correlations lifts the magnetic degeneracy on a nanometer length scale, enabling long-range magnetic order in the Na derivative. The degree of frustration, mediated by residual disorder, contributes to the rather differing pathways to a single, stable magnetic ground state in these two related compounds. This study demonstrates how nanoscale structural distortions that cause local-scale perturbations can lift the ground-state degeneracy and trigger macroscopic magnetic order.
- Received 2 March 2019
- Revised 29 November 2019
- Corrected 20 May 2020
DOI:https://doi.org/10.1103/PhysRevB.101.024423
©2020 American Physical Society
Physics Subject Headings (PhySH)
Corrections
20 May 2020
Correction: Additional information for the Fulbright Foundation-Greece support statement has been inserted.