Importance of stacking to the collinear magnetic phases of the geometrically frustrated antiferromagnet CuFeO₂

The correct stacking of hexagonal layers is used to obtain accurate estimates for the exchange and anisotropy parameters of the geometrically frustrated antiferromagnet CuFeO₂. Those parameters are highly constrained by the stability of a collinear metamagnetic phase between fields of 13.5 and 20 T. Constrained fits of the spin-wave frequencies of the collinear ↑↑↓↓ phase below 7 T are used to identify the magnetic unit cell of the metamagnetic ↑↑↑↓↓ phase, which contains two hexagonal layers and 10 Fe³⁺ spins.