Universality of spin-phonon splitting in AF

Universal Exchange-Driven Phonon Splitting in Antiferromagnets.
Ch. Kant, M. Schmidt, Zhe Wang, F. Mayr, V. Tsurkan, J. Deisenhofer, and A. Loidl
Phys. Rev. Lett. 108, 177203 (2012)

Magnetic properties of the investigated TMMOs. (a) Magnetic unit cell showing the AF order along [111]. (b) Splitting into phonon modes with eigenfrequencies omega perp and omega par. (c) Nearest-neighbor coupling J1 and dominant next-nearest neighbor coupling J2. (d) Neel temperatures vs J2S(S+1) using values for J2 taken from Ref. [26] in comparison to the mean-field expectation (dashed line).