Soliton-Magnon Interference Observed by Antiferromagnetic Resonance in TMMC

Abstract

By means of antiferromagnetic resonance in the linear-chain antiferromagnet (CH3)4NMnCl3 (TMMC) we have studied the effect of sine-Gordon solitons on the q* = 0 magnon. Like in ferromagnetic chains the phase coupling between solitons and magnons results in a broadening of the magnon line width which is proportional to the soliton density and shows a drastic dependence on temperature and on the external magnetic field.

Truncated forms of the second-rank orthorhombic Hamiltonians used in magnetism and electron magnetic resonance (EMR) studies are invalid—Why it went unnoticed for so long?

“…For the study of soliton-magnon interference observed in antiferromagnetic resonance (AFMR) in TMMC similar Hamiltonian as in Eq. (9c), but with the parameters replaced as follows D z by D and D x by E, was used in [50]. For the study of internal oscillations of solitons in TMMC 1-d Hamiltonian similar Hamiltonian as in Eq.…”

“…(11b) used in [57] and [50,51] differ from the usual conventional ZFS parameters D and E in Eq. (2).…”

Internal oscillations of kink-type solitons in one-dimensional antiferromagnets like TMMC

“…and describes the gap of the highest (out-of-plane) magnon branch. For TMMC we have H c 100 kOe and H SF 12 kOe [10]. The usual elementary excitations important for 1D magnets, magnons and kinks, can easily be extended to the GSG case, equation (2).…”

“…SF , which determines the magnon gap in the SG limit K 2 /K → 0 and K 6 = 0 [10]. ϕ 0 denotes the ground state orientation of l for arbitrary values of K 2 and K 6 (see figure 1).…”

“…Recently it was shown [9] that this out-of-plane mode for 1D antiferromagnets has essentially quantum nature, even for spin S = 5/2, which is usually considered as semiclassical. For easy-plane antiferromagnets like TMMC out-ofplane magnons are generally of much higher frequency than in-plane magnons, which interact with the solitons and are manifested in soliton-magnon interference [10]. Such oscillations are usually described in terms of a sine-Gordon (SG) equation.…”