Abstract
FeV2O4 is found to show three structural transitions and successive paramagnetic(PM)-
collinear ferrimagnetic(CFI)-nocollinear ferrimagnetic(NCFI) magnetic transitions. The tetragonal-
orthorhombic structural transition associated with PM-CFI transition is accompanied by the ap-
pearance of an energy gap with a high magnitude in the magnetic excitation spectrum, which is a
consequence of the strong spin-orbital coupling induced anisotropy at Fe2+ A site. The comparison
of Fe spin waves at CFI and noncollinear ferrimagnetic/ferroelectric phases shows no signi cant spin
frustration of Fe2+ spins at A site, suggesting A-site Fe2+ spins may not play a main role in the
appearance of the ferroelectricity. Spin wave damping shows a rapid increase when NCFI transforms
to CFI phase, indicating a possible V3+ spin
uctuations at B site prior to their true canting in
the NCFI phase. The spin wave broadening is also observed at the zone boundary without the spin
wave softening, which is discussed in terms of the e ect of magnon-phonon coupling.
Understanding the
