Abstract:
The nonlinear response of magnetization of antiferromagnetic nanoparticles under the action of an alternating magnetic field of extremely high frequency is investigated. The case of uniaxial magnetic anisotropy of antiferromagnet sublattices with an external constant field imposed along the easy axis is considered. The solution of the inertial Landau—Lifshitz–Gilbert equation by the method of successive approximations made it possible to obtain analytical expressions for the components of the nonlinear magnetic susceptibility tensor of the second and third orders. The dynamic magnetic hysteresis at extremely high frequencies in the nutation resonance region is calculated. It is shown that both the nonlinear susceptibility and the shape of the hysteresis loop in the THz frequency range significantly depend on the frequency of the alternating field, as well as on the inertial relaxation time. It has been demonstrated that such nonlinear effects as frequency doubling and the appearance of weak subharmonic resonance peaks observed in the frequency region of antiferromagnetic resonance are also reproduced in the region of nutation resonance.
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