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Exchange‐spring behavior of nanocrystalline (NdPr) 4 Fe 71 Co 5 Cu 0.5 Nb 1 B 18.5
Author(s) -
Manjura Hoque S.,
Khan F. A.,
Hakim M. A.
Publication year - 2007
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.200622575
Subject(s) - coercivity , materials science , analytical chemistry (journal) , nanocrystalline material , annealing (glass) , atmospheric temperature range , magnetization , amorphous solid , hysteresis , melt spinning , magnetic hysteresis , curie temperature , alloy , nuclear magnetic resonance , ferromagnetism , condensed matter physics , metallurgy , chemistry , crystallography , magnetic field , thermodynamics , nanotechnology , spinning , physics , composite material , chromatography , quantum mechanics
An amorphous alloy of composition (NdPr) 4 Fe 71 Co 5 Cu 0.5 Nb 1 B 18.5 prepared by a melt spinning technique in an argon atmosphere has been studied to observe exchange‐spring behavior in the nanocrystalline state. Hysteresis loop measurements at room temperature revealed that the highest value of the coercivity, H c , of 4.08 kOe has been obtained for the sample annealed at 913 K for 10 min. At this annealing temperature ( BH ) max and M r / M s have been found to be 11.06 MGOe and 0.716, respectively. Steep recoil curves of the samples annealed at 873 and 973 K show typical characteristics of the exchange‐spring mechanism having smaller loop area. The temperature dependences of H c , M r / M s and ( BH ) max in the range of 5 to 380 K generally decrease with the increase of temperature. From the temperature dependence of the hysteresis loop parameters, it has been found that at 5 K the values of H c and ( BH ) max are 6.89 kOe and 13.72 MGOe respectively for the sample annealed at 873 K for 10 min and 6.69 kOe and 13.74 MGOe respectively for the sample annealed at 923 K for 10 min. A change in the shape of the hysteresis loops was observed at temperatures below 100 K, related to the spin reorientation in the hard magnetic phase. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)