Title :
Jumps of magnetic polarization in Sm2Co17-based magnets
Author :
Handstein, A. ; Eckert, D. ; Müller, K.H. ; Wall, B. ; Rodewald, W.
Author_Institution :
Inst. fur Festkorper und Werkstofforschung e.V., Dresden, Germany
fDate :
3/1/1994 12:00:00 AM
Abstract :
At temperatures below 8.2 K large spontaneous jumps in the demagnetization curve of Sm2(Co,Cu,Fe,Zr)17 magnets with high coercivity were detected. For different samples no correlations concerning the onset, the depth or the number of jumps could be observed. Systematic investigations showed the following results: i) The emergence and the number of jumps depend on the temperature, the field sweeping rate and the sample dimensions. ii) The onset of jumps is shifted to smaller applied fields with decreasing temperature. iii) The cooling conditions have a strong influence. These results have definitely shown that the observed polarization jumps are due to thermal instabilities because of the small heat capacity and poor thermal conductivity in agreement with a local heating model
Keywords :
cobalt alloys; coercive force; copper alloys; demagnetisation; ferromagnetic properties of substances; iron alloys; permanent magnets; samarium alloys; specific heat of solids; thermal conductivity of solids; zirconium alloys; 8.2 K; Sm2(Co,Cu,Fe,Zr)17 magnets; Sm2(CoFeCuZr)17; Sm2Co17-based magnets; cooling conditions; demagnetization curve; field sweeping rate; local heating model; magnetic polarization; polarization jumps; poor thermal conductivity in; sample dimensions; small heat capacity; thermal instabilities; Demagnetization; Helium; Magnetic field measurement; Magnetic fields; Magnetic hysteresis; Magnetization reversal; Magnets; Polarization; Samarium; Temperature dependence;
Journal_Title :
Magnetics, IEEE Transactions on
