<p>Ferrimagnetic materials exhibiting remanence can be used to achieve unidirectional electromagnetic-field propagation in the form of magnetoplasmons (MPs) in the subwavelength regime. This study investigates the MP properties and various guiding modes in a hollow cylindrical waveguide made of materials that exhibit remanence. Pattern analysis and numerical simulations are used to demonstrate that dispersion relationships and electromagnetic-field distribution are strongly affected by the operating frequency and physical dimensions of the structure. In addition, the existence of two different guiding modes is proved, namely regular and surface-wave modes. By adjusting the operating frequency and reducing the diameter of the hollow cylinder, the regular mode can be suppressed so as to only retain the surface-wave mode, which enables unidirectional MP propagation in the cylindrical waveguide. Moreover, the unidirectional surface-wave mode is robust to backscattering due to surface roughness and defects, which makes it very useful for application in field-enhancement devices.</p>