Title :
AC losses in grain oriented Tb0.3Dy0.7Fe1.95
Author :
Greenough, R.D. ; Schulze, M.
Author_Institution :
Dept. of Appl. Phys., Hull Univ., UK
fDate :
9/1/1990 12:00:00 AM
Abstract :
The complex permeability as a function of frequency has been investigated in grain-oriented Tb0.3Dy0.7Fe1.95. Domain-wall effects increase the eddy-current losses in small applied (DC) fields, but with fields large enough to obtain optimum magnetomechanical coupling (k 33), the losses agree with the theory for macroscopic eddy currents. The data provide an indication of the inherent bandwidth limitations of devices incorporating this material and are also relevant to the correction of dynamic k33 measurements determined by the resonance-antiresonance technique. It is pointed out that a reliable scaling of dynamic k33 data according to change in permeability with frequency is hampered by the rate of change of permeability in the range 1 to 10 kHz, and this difficulty demonstrates the need for a frequency-dependent loss mechanism to be included in the analysis of the resonance-antiresonance characteristics
Keywords :
dysprosium alloys; eddy current losses; ferromagnetic properties of substances; iron alloys; magnetic domain walls; magnetic permeability; magnetomechanical effects; terbium alloys; 1 to 10 kHz; AC losses; Tb0.3Dy0.7Fe1.95; bandwidth limitations; complex permeability; domain wall effects; dynamic k33 data; eddy-current losses; ferromagnet; frequency-dependent loss mechanism; grain oriented; optimum magnetomechanical coupling; resonance-antiresonance technique; scaling; Couplings; Frequency; Iron; Magnetic domain walls; Magnetic field measurement; Magnetic flux; Magnetic separation; Magnetization; Magnetostriction; Permeability measurement;
Journal_Title :
Magnetics, IEEE Transactions on
