The magnetic properties of annealed graphite-coated Ni and Co nanocrystals

Author

Block, J.A. ; Parvin, K. ; Alpers, J.L. ; Sezen, T. ; LaDuca, R. ; Host, J.J. ; Dravid, V.P.

Author_Institution

Dept. of Phys., San Jose State Univ., CA, USA

Volume

34

Issue

4

fYear

1998

fDate

7/1/1998 12:00:00 AM

Firstpage

982

Lastpage

984

Abstract

Magnetic studies of graphite-coated nanocrystals of nickel and cobalt (5-50 nm) synthesized in a special fullerene are chamber are reported. Magnetization measurements as a function of temperature in the range 20-900°C indicate the ferromagnetic nature of the nanocrystals. Upon heating and recooling of the nanocrystals a larger magnetization was measured, The dependence of room temperature M_s, M_r, and H_c of the nanocrystals on annealing temperature is reported. The data are consistent with increase in size of single domain particles, or transition of the nanocrystals from single domain to multi-domain due to particle size growth in the annealing process

Keywords

annealing; cobalt; ferromagnetic materials; magnetic domains; magnetic particles; magnetisation; nanostructured materials; nickel; particle size; 20 C; 20 to 900 C; 5 to 50 nm; C₆₀; Co; Ni; annealed graphite-coated Co nanocrystals; annealed graphite-coated Ni nanocrystals; annealing temperature; ferromagnetic nanocrystals; fullerene; graphite-coated nanocrystals; heating; magnetic properties; magnetic studies; magnetization; magnetization measurements; multi-domain particles; particle size growth; recooling; room temperature; single domain particles; Annealing; Cobalt; Magnetic properties; Magnetic separation; Magnetization; Nanocrystals; Nickel; Physics; Protection; Temperature dependence;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.706331

Filename

706331