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Title: Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys

Abstract

High resolution imaging and electron diffraction confirm that in the as-quenched state the structure of Fe{sub 79.7−x}Cr{sub x}Nb{sub 0.3}B{sub 20} (x = 11–13 at. %) melt-spun ribbons is completely amorphous, independent of the Cr content. Energy-dispersive X-ray spectroscopy mapping emphasizes clearly the presence of Fe and Cr clusters varying from approximately 1 to 2–3 nm in size with the increase of Cr content from 11 to 13 at. %. The Fe and Cr atoms segregate the atomic scale to form nanometer sized clusters, influencing strongly the macroscopic magnetic behavior. The Curie temperature of the system, T{sub C}{sup system}, confirmed by the magnetic susceptibility versus temperature measurements, gives the strength of the magnetic interactions between clusters. The inter-cluster interactions are much stronger for lower contents of Cr, the microstructure is less uniform, and T{sub C}{sup system} increases from 290 K for 13 at. % Cr to 330 K for 11.5 at. % Cr. The whole system transforms to a ferromagnetic state through interactions between the clusters. Zero-field cooling and field cooling curves confirm the cluster behavior with a blocking temperature, T{sub b}, of about 250 K. Above T{sub b}, the ribbons behave as a superferromagnetic system, whilst below the blocking temperature a classical ferromagnetic behavior is observed.

Authors:
; ; ; ; ;  [1]
  1. National Institute of Research and Development for Technical Physics, 700050 Iasi (Romania)
Publication Date:
OSTI Identifier:
22409962
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; BORON ALLOYS; CHANNELING; CHROMIUM ALLOYS; CURIE POINT; ELECTRON DIFFRACTION; FERROMAGNETIC MATERIALS; FERROMAGNETISM; IRON BASE ALLOYS; MAGNETIC SUSCEPTIBILITY; METALLIC GLASSES; MICROSTRUCTURE; NANOSTRUCTURES; NIOBIUM ALLOYS; TEMPERATURE DEPENDENCE; TEMPERATURE MEASUREMENT; X-RAY SPECTROSCOPY

Citation Formats

Chiriac, H., Whitmore, L., Grigoras, M., Ababei, G., Stoian, G., and Lupu, N., E-mail: nicole@phys-iasi.ro. Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys. United States: N. p., 2015. Web. doi:10.1063/1.4916756.
Chiriac, H., Whitmore, L., Grigoras, M., Ababei, G., Stoian, G., & Lupu, N., E-mail: nicole@phys-iasi.ro. Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys. United States. doi:10.1063/1.4916756.
Chiriac, H., Whitmore, L., Grigoras, M., Ababei, G., Stoian, G., and Lupu, N., E-mail: nicole@phys-iasi.ro. Thu . "Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys". United States. doi:10.1063/1.4916756.
@article{osti_22409962,
title = {Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys},
author = {Chiriac, H. and Whitmore, L. and Grigoras, M. and Ababei, G. and Stoian, G. and Lupu, N., E-mail: nicole@phys-iasi.ro},
abstractNote = {High resolution imaging and electron diffraction confirm that in the as-quenched state the structure of Fe{sub 79.7−x}Cr{sub x}Nb{sub 0.3}B{sub 20} (x = 11–13 at. %) melt-spun ribbons is completely amorphous, independent of the Cr content. Energy-dispersive X-ray spectroscopy mapping emphasizes clearly the presence of Fe and Cr clusters varying from approximately 1 to 2–3 nm in size with the increase of Cr content from 11 to 13 at. %. The Fe and Cr atoms segregate the atomic scale to form nanometer sized clusters, influencing strongly the macroscopic magnetic behavior. The Curie temperature of the system, T{sub C}{sup system}, confirmed by the magnetic susceptibility versus temperature measurements, gives the strength of the magnetic interactions between clusters. The inter-cluster interactions are much stronger for lower contents of Cr, the microstructure is less uniform, and T{sub C}{sup system} increases from 290 K for 13 at. % Cr to 330 K for 11.5 at. % Cr. The whole system transforms to a ferromagnetic state through interactions between the clusters. Zero-field cooling and field cooling curves confirm the cluster behavior with a blocking temperature, T{sub b}, of about 250 K. Above T{sub b}, the ribbons behave as a superferromagnetic system, whilst below the blocking temperature a classical ferromagnetic behavior is observed.},
doi = {10.1063/1.4916756},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}