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Recoil hysteresis and temperature dependence of coercivity of Nd 4 Fe 73.5 Co 3 Hf 0.5 Ga 0.5 B 18.5
Author(s) -
Manjura Hoque S.,
Hakim M. A.,
Khan F. A.,
Nghi N. H.
Publication year - 2008
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200723057
Subject(s) - coercivity , remanence , recoil , hysteresis , materials science , analytical chemistry (journal) , atmospheric temperature range , annealing (glass) , magnetic hysteresis , nuclear magnetic resonance , condensed matter physics , magnetization , chemistry , magnetic field , thermodynamics , atomic physics , metallurgy , physics , quantum mechanics , chromatography
Recoil hysteresis and temperature dependence of coercivity have been measured for the sample of composition Nd 4 Fe 73.5 Co 3 Hf 0.5 Ga 0.5 B 18.5 prepared by rapid quenching method with a wheel speed of 25 m/s and after subsequent annealing in an evacuated quartz tube under a pressure of 10 –5 mbar at different temperatures and times. In the optimum and over‐annealed condition, recoil hysteresis loops have been measured by the application of progressively increasing negative field and successive withdrawal to the remanence and found to have steep recoil loop and small recoil area, which is characteristic to exchange‐biased system. Temperature dependence of coercivity in the range of 5 K to 380 K has been measured for the sample of composition Nd 4 Fe 73.5 Co 3 Hf 0.5 Ga 0.5 B 18.5 . Variation in the shape of the hysteresis loop has been observed in this temperature range. In the low temperature region i.e. below 150 K hysteresis loops are constricted due to spin reorientation of Nd 2 Fe 14 B at 135 K while above this temperature the hysteresis loops are characterized by convex M ( H ) curve similar to single‐phase permanent magnet. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)