Magnetoelastic Oscillations in an Antiferromagnetic Nanowire

Abstract

Background. This paper studies magnetoelastic oscillations in an antiferromagnetic nanowire. Small magnetoelastic oscillations in the antiferromagnetic nanowire which can be caused by spin current are investigated in this work. Significant interactions between the magnetic and elastic subsystems are expected for antiferromagnetic nanostructures. An important consideration is the consideration of finite-size antiferromagnets, which are more interesting for experimental studies but at the same time are more complex for theoretical description due to the need to address the boundary conditions.Objective. The aim of the study is determination of the mutual influence of the magnetic and elastic subsystems in antiferromagnets and studying the features of this interaction, which can be interesting in terms of practical applications.Methods. The Lagrangian approach to describing the dynamics of the system is used. The equations of motion, obtained from the variational principle for the corresponding action functional, are studied. The dispersion relations for magnetoelastic and elastic-magnetic waves propagating perpendicular to the nanowire axis are established and analyzed.Results. It is shown that in the case of high-temperature antiferromagnetism, there is a qualitative change in the spectrum of magnetoelastic waves even for small coefficient of connection between the magnetic and elastic subsystems. For the geometry considered, which corresponds to the nanowire, the influence of the boundary conditions leads to dimensional quantization of frequencies. The corresponding quantization law is determined analytically for magnetoelastic waves.Conclusions. The dispersion relations for the magnetoelastic and the elastic-magnetic waves propagating perpendicular to the axis of the nanowire of the cubic collinear antiferromagnet are determined. The importance of taking into account the magnetoelastic interaction in an antiferromagnet with the decreasing of its size to nanometer orders is shown. The finiteness of the sample leads to the discretization of the frequencies of the magnetoelastic waves.