INVESTIGADORES
DE BIASI Emilio
artículos
Título:
Ferromagnetic resonance in amorphous nanoparticles
Autor/es:
DE BIASI EMILIO; ZYSLER ROBERTO; RAMOS CARLOS; ROMERO HÉCTOR
Revista:
PHYSICA B - CONDENSED MATTER
Referencias:
Año: 2004 vol. 354 p. 286 - 289
ISSN:
0921-4526
Resumen:
We present the results of ferromagnetic resonance (FMR) measurements on noninteracting amorphous nanoparticle
systems (Co0.25Ni0.75)65B35 (CNB2) and (Fe0.25Ni0.75)50B50 (FNB2) in the temperature range 10300 K.The hightemperature
results show symmetric lineshapes that indicate a low value of effective anisotropy.When cooling the
linewidth increases and the lineshapes lose their symmetric shape.The lineshape can be interpreted as due to slightly
elongated particles.In CNB2, we observe a sharp intensity maximum at T=60K, followed by a linewidth maximum
and resonance field minimum at T=50 K.The same tendency is observed in FNB2, with an intensity maximum near0.25Ni0.75)65B35 (CNB2) and (Fe0.25Ni0.75)50B50 (FNB2) in the temperature range 10300 K.The hightemperature
results show symmetric lineshapes that indicate a low value of effective anisotropy.When cooling the
linewidth increases and the lineshapes lose their symmetric shape.The lineshape can be interpreted as due to slightly
elongated particles.In CNB2, we observe a sharp intensity maximum at T=60K, followed by a linewidth maximum
and resonance field minimum at T=50 K.The same tendency is observed in FNB2, with an intensity maximum nearT=60K, followed by a linewidth maximum
and resonance field minimum at T=50 K.The same tendency is observed in FNB2, with an intensity maximum nearT=50 K.The same tendency is observed in FNB2, with an intensity maximum near
T40 K, with an increment in the linewidth and simultaneous decrease of the resonance field down to the lowest
temperature, T=10K.Previous magnetization measurements on these systems indicate large surface effects in the same
temperature region of the observed anomalies.This picture, together with simulations, permits us to explain the FMR
behaviour.40 K, with an increment in the linewidth and simultaneous decrease of the resonance field down to the lowest
temperature, T=10K.Previous magnetization measurements on these systems indicate large surface effects in the same
temperature region of the observed anomalies.This picture, together with simulations, permits us to explain the FMR
behaviour.T=10K.Previous magnetization measurements on these systems indicate large surface effects in the same
temperature region of the observed anomalies.This picture, together with simulations, permits us to explain the FMR
behaviour.