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Interparticle Interactions in (Fe 1—x Ni x ) 100—y B y Magnetic Nanoparticles
Author(s) -
Romero H.,
Ortega A.,
Zysler R.,
Ramos C.,
De Biasi E.,
Fiorani D.
Publication year - 2000
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 - 10.1002/1521-3951(200007)220:1<401::aid-pssb401>3.0.co;2-k
Subject(s) - magnetization , brillouin and langevin functions , superparamagnetism , materials science , condensed matter physics , dispersion (optics) , amorphous solid , nanoparticle , magnetic field , nanotechnology , physics , chemistry , crystallography , optics , quantum mechanics
In order to study the effect of interparticle interactions the magnetic properties of amorphous (Fe 1— x Ni x ) 100— y B y nanoparticles (0.25 < x < 0.75 and y ≈ 0.50) have been investigated by magnetization measurements in a homogeneous dispersion of particles in a PVP polymer and in powder samples. The dispersed samples show the characteristic behaviour of an assembly of independent nanosized particles, characterized by a narrow size distribution, with a sharp maximum of zero field cooled (ZFC) magnetization whereas the field cooled (FC) magnetization increases continuously with decreasing temperature. The magnetization in the superparamagnetic regime is satisfactorily fitted to a superposition of Langevin functions due to the volume distribution. On the other hand, in the powder samples, where strong interparticle interactions are expected, the M ZFC shows a wider maximum with a significant increase of the temperature at which it occurs and M FC presents a plateau at low temperature. The magnetization curves for the powder samples can be fitted to a Langevin function if interparticle interactions are taken into account by introducing a mean‐field‐like term in the argument.