On July 9th, magnons—fundamental quasi-particles representing low-energy excitations of spin waves in magnetic materials—are being considered as promising information carriers for the next generation of spintronic devices. Nevertheless, the ferromagnetic resonance frequency of conventional ferromagnetic materials is confined to the gigahertz range, severely limiting their potential applications in the terahertz band. Although antiferromagnets exhibit higher resonance frequencies, their manipulation and detection are challenging due to their zero net magnetization. Consequently, the creation of a magnetic material system that offers both a high-frequency response and ease of manipulation has emerged as a critical and urgent issue that needs to be addressed.