We demonstrate a novel method for enhancing the coercivity of magnetic materials. Granular Fe‐(SiO2) solids have been fabricated over a wide volume fraction range from 15% to 100%. Giant magnetic coercivity, as high as 2500 Oe, has been observed in granular solids in which the isolated Fe granules are only nanometers in size. Across the whole volume fraction range magnetic coercivity experiences dramatic variations due to the change of granular size and percolation effects.

Topics
Granular materials, Magnetic materials, Metal oxides
1.
B. Abeles, in Applied Solid State Science: Advances in Materials and Device Research, edited by R. Wolfe (Academic, New York, 1976), p. 1.
2.
J. A. A. J.
Perenboom
,
P.
Wyder
, and
F.
Meier
,
Phys. Rep.
78
,
173
(
1981
).
Google Scholar
Crossref
Search ADS
 
3.
W. P.
Halperin
,
Rev. Mod. Phys.
58
,
533
(
1986
).
Google Scholar
Crossref
Search ADS
 
4.
A. H. Morrish, The Physical Principles of Magnetic (Wiley, New York, 1965).
5.
H. N.
Bertram
 and
A. K.
Bhatia
,
IEEE Trans. Magn.
MAG‐9
,
127
(
1973
).
Google Scholar
 
6.
E. F.
Kneller
 and
F. E.
Luborsky
,
J. Appl. Phys.
34
,
656
(
1963
).
Google Scholar
Crossref
Search ADS
 
7.
E. P.
Wohlfarth
,
Proc. R. Soc. (London) A
232
,
208
(
1955
).
Google Scholar
 
8.
A. H.
Morrish
 and
S. P.
Yu
,
J. Appl. Phys.
26
,
1049
(
1955
).
Google Scholar
Crossref
Search ADS
 
9.
E. H.
Frei
,
S.
Shtrikman
, and
D.
Treves
,
Phys. Rev.
106
,
446
(
1957
).
Google Scholar
Crossref
Search ADS
 
10.
I. S.
Jacobs
 and
C. P.
Bean
,
Phys. Rev.
100
,
1060
(
1955
).
Google Scholar
Crossref
Search ADS
 
This content is only available via PDF.
© 1987 American Institute of Physics.
1987
American Institute of Physics
You do not currently have access to this content.