Pinning of Solitons in Crystal Field of Magnetic

The energy of pinning of solitons in the Heisenberg ferromagnetic is estimated and verified in the numerical experiment with a discrete chain. The 4π-kink fixed in a chain of spins is found, as well as the magnetic field being critical for solitons and its association with the kink velocity limit. The obtained results are juxtaposed with models having the various anharmonicity in the Frenkel-Kontorova chain, the kink amplitude and energy of pinning are compared. It is shown that restriction of the phase space by velocities of solitons in the offered model brings to the smaller density of kinks in crystal CsNiF₃ as compared to the result of the Frenkel-Kontorova model. It is found that a difference in density of solitons in Heisenberg ferromagnetic and those in Frenkel-Kontorova model for crystal CsNiF₃ increases with the magnetic field growth.