Observation of a gap in the spin-wave spectrum in YFeO3 upon an orientational transition in a magnetic field
Balbashov A. M., Berezin A. G., Gufan Yu. M., Kolyadko G. S., Marchukov P. Yu., Nikolaev I. V., Rudashevskii E. G.
During spin flip in YFe03 induced by a magnetic field H||a, the antiferromagnetic resonant frequency does not vanish. It is predicted theoretically that the observed gap will have the behavior Vo~4x\\This transition, continuous in H, does not have the properties of a second-order phase transition.