Determination of the magnetic viscosity in SmCo5-xCux alloys by pulsed-field method

The coercive held of annealed SmCo3Cu2 and SmCo2.5Cu2.5 alloys was measured for different pulsed-held rate, dH/dt, for temperatures between 4 and 600 K. The temperature dependency of the magnetic viscosity parameter, S-v, was investigated in this range of temperatures. S-v was determined from two di fferent pulsed-field rates. We found that at a given temperature the magnet ic viscosity is independent of dH/dt. The curve S-v versus temperature show s a maximum around 100 K. The S-v dependence of H-c shows also a maximum. A n empiric equation that describes S-v versus H-c was found. The tau (0) val ue of these magnets was estimated. It is suggested that measurements in pul sed field with high dH/dt are very practical method to determine the viscos ity parameter. (C) 2001 Elsevier Science B.V. All rights reserved.