Spin reorientation transition and spin dynamic study of perovskite orthoferrite TmFeO3 detected by Electron Paramagnetic Resonance

In this paper, we apply and explore the Electron Paramagnetic Resonance (EPR) spectra together with magnetic susceptibility to study the spin reorientation transition and spin interaction mechanism of the perovskite orthoferrites TmFeO3. The combined experimental measurements of the magnetic curves (M-T curve) and EPR spectra confirms an antiferromagnetic transition at 85 K with a reentering ferromagnetic state due to the spin reorientation behavior. In high-temperature region of T > 90 K, three notable resonance peaks simultaneously occur in one EPR spectrum of the same temperature, indicating the sign of multiple magnetic phases (canted AFM or weak FM and PM phase). In low-temperature region (T 85 K, the spin reorientation of 85 - 65 K, the ferromagnetic interaction of the lower temperature, respectively. Above 90 K, the spin relaxation mechanism is determined by the mixture of spin-spin and spin-lattice interactions. Below 85 K, transverse relaxation rate increases as the decrease of temperature, in agreement with the weakened fluctuating internal field in this temperature regime. Such an EPR detection offer a new route for the exhaustive clarification of strong spin coupling in antiferromagnetic materials.