Partial Antiferromagnetic Helical Order in Single Crystal Fe3PO4O3

December 3, 2020
Partial Antiferromagnetic Helical Order in Single Crystal Fe3PO4O3
Small single crystal of Fe3PO4O3 (upper left). Neutron diffraction data map in the hk0-plane near (0 0 3/2) at 4 K (left) and corresponding calculated scattering from a resolution-limited ring of radius 98 Å (right). The upper right inset shows the non-convolved ring of scattering.

Scientific Achievement

Helical magnetic order in  Fe3PO4O3  has a well-defined ordering wavevector magnitude, but not direction.

Significance and Impact

Results suggest Fe3PO4O3 is an antiferromagnetic analogue of the ferromagnetic material MnSi, and both have partial order related to the blue phase found in liquid crystals. This favors the formation of skyrmions that may prove useful for spintronic applications.

Research Details

  • Neutron diffraction in a sub-mm Fe3PO4O3 single crystal showed rings of scattering arising from the partially disordered helical structure. 
  • Theory shows that a Heisenberg model with first and second neighbor interactions leads to a quasi-degenerate manifold of wavevectors resulting in the partially ordered state.

“Partial Antiferromagnetic Helical Order in Single Crystal Fe3PO4O3,”
Colin Sarkis, Michael Tarne, James Neilson, Huibo Cao, Ethan Coldren, Martin Gelfand and Kathryn Ross,
Physical Review B, 101, 1084417 (2020).