This paper presents a complete study on the influence of a dc external magnetic field on polaritons confined in uniaxial antiferromagnetic cylinders. Using different values for the cylinder radius and the strength of the external field, we study the effect of these external parameters on the dispersion relation of confined mixed modes. It is shown that, for any finite value of the static magnetic field, only modes with their rf magnetic field perpendicular to the anisotropy axis can be found confined in the sample. Numerical results are presented for the uniaxial Heisenberg antiferromagnet ${\mathrm{MnF}}_2$.

• Received 8 December 1992

DOI:https://doi.org/10.1103/PhysRevB.48.9839