Magnetomechanical damping by polycrystalline TbDy

Magnetomechanical damping by polycrystalline TbDy

Vibration damping in polycrystalline TbDy alloys was studied at cryogenic temperatures. Mechanical hysteretic losses were measured at various strains, frequencies, and loading configurations at 77 K. Some textured TbDy materials demonstrated 22.6% energy dissipation in mechanical measurements at low frequency ~0.01 Hz! and a mean logarithmic decrement of 0.23 at a higher frequency ~25 kHz!. Ult...

Magnetomechanical effects in textured polycrystalline Tb76Dy24

Uniaxial stress-strain measurements were performed on polycrystalline Tb76Dy24 alloys which exhibit ‘‘giant magnetostriction’’ at cryogenic temperatures. The Young’s moduli were reduced by up to a factor of five at 77 K, in comparison to their values at 300 K. We attribute this reduction to a mechanical compliance from domain rotation. Large mechanical hysteresis is also found in nominally elas...

Magnetomechanical Damping and Domain Structures in Grain Oriented Silicon Steel Sheets

Intrinsic and non-local Gilbert damping in polycrystalline nickel studied by Ti:Sapphire laser fs spectroscopy

The use of femtosecond laser pulses generated by a Ti:Sapphire laser system allows us to gain an insight into the magnetization dynamics on time scales from sub-picosecond up to 1 ns directly in the time domain. This experimental technique is used to excite a polycrystalline nickel (Ni) film optically and probe the dynamics afterwards. Different spin wave modes (the Kittel mode, perpendicular s...

Damping by branching

Man-made slender structures are known to be sensitive to high levels of vibration due to their flexibility which often cause irreversible damage. In nature, trees repeatedly endure large amplitudes of motion, mostly caused by strong climatic events, yet with minor or no damage in most cases. A new damping mechanism inspired by the architecture of trees is identified here and characterized in th...