Magnetic and magneto-lattice dynamics in GdMn2O5

The dynamics of magnetoelectric RMn2O5 crystals (R = Eu and Gd) was studied in the frequency and temperature ranges 20-300 GHz and 5-50 K, respectively. The crystals possessed magnetic and ferroelectric long-range order and had close transition temperatures, T-N,T- C similar or equal to 36 and 30 K for R= Eu and Gd, respectively. Mixed magneto-lattice excitations were observed in GdMn2O5; the excitations were most intense near the transition temperature T similar or equal to 30 K at frequencies close to the antiferromagnetic resonance frequencies of the Mn subsystem. Along with the antiferromagnetic resonance of the Mn subsystem, the ferromagnetic resonance of the Gd subsystem was observed in GdMn2O5 in an external magnetic field. No such dynamics was characteristic of EuMn2O5. (C) 2003 MAIK Nauka / Interperiodica.