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Nanocrystalline soft magnetic materials: intergrain coupling and spin freezing effects
Author(s) -
Škorvánek I.,
Kováč J.,
Kötzler J.
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200301669
Subject(s) - nanocrystalline material , materials science , condensed matter physics , curie temperature , amorphous solid , magnetization , magnetic hysteresis , atmospheric temperature range , spin glass , hysteresis , relaxation (psychology) , decoupling (probability) , magnetic shape memory alloy , amorphous metal , magnetic domain , ferromagnetism , metallurgy , thermodynamics , magnetic field , nanotechnology , crystallography , chemistry , physics , quantum mechanics , control engineering , engineering , psychology , social psychology , alloy
The static and dynamic magnetic properties of the nanocrystalline soft magnetic FeNbB alloys consisting of Fe‐nanograins embedded in an amorphous matrix were investigated by means of dc and ac susceptibility, magnetization and hysteresis loop measurements in a wide temperature range. We show that these alloys exhibit particular complex magnetic behaviour versus temperature. The spin‐glass like behaviour at cryogenic temperatures is followed by a very soft magnetic behaviour at intermediate temperatures, and finally, a marked magnetic hardening due to decoupling between the nanograins is observed when temperature approaches the Curie temperature of the amorphous matrix. Upon further increase of temperature, the thermal relaxation of magnetization plays a dominant role. The results are discussed within a model that takes into account the presence of weakly magnetic Nb‐rich shells around the nanocrystalline grains.