Control of antiferromagnetic resonance and the Morin temperature in cation doped α-Fe2-xMxO3 (M = Al, Ru, Rh, and In)

Antiferromagnets are one of the few candidate materials that can work at THz frequency and are, therefore, a potential material for THz technology recently attracting interest from high-speed communication and sensing applications. In this work, we investigate an antiferromagnetic resonant frequency ( ω r) tunability for cation doped α-Fe2O3. It is found that, with various cation dopants (Al, Ru, Rh, and In), the resonant frequency can be tuned in a range between a millimeter-wave band and a THz band. We also complementally discuss the mechanism of the Morin temperature ( T M) shift upon cation doping by the temperature and dopant dependence of ω r. A good frequency tunability shown in this work suggests that cation doped α-Fe2O3 is a useful material for millimeter-wave and THz applications.