FERROMAGNETIC RESONANCE IN TERFENOL-D AT 17 GHz

Ferromagnetic resonance measurements have been performed on several samples of Terfenol-D (Dy0.73Tb0.27Fe1.95) at 16.95 GHz and over the temperature range 293 to 305 K. We find that the first magnetocrystalline anisotropy constant, obtained from one sample under nearly zero stress, is K1 = (-1.4±1.0)× l06erg/cm3 at 294 K. Our measurement is distinct from quasistatic torque measurements in that the lattice does not deform during the measurement and, hence, the anisotropy contribution due to magnetoelastic strain does not enter. The bare anisotropy constant, unmodified by static elastic strain, is and . The samples exhibited hysteresis; the position of FMR shifted by 4.0 kOe between measurements made with the magnetic field increasing and those made with the field decreasing.