Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-02T18:47:24.733Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructural defects in γ-Fe2O3 particles

Published online by Cambridge University Press:  31 January 2011

Ernest L. Hall  and
Ami E. Berkowitz
Ernest L. Hall
Affiliation:
General Electric Company, Corporate Research and Development, Schenectady, New York 12301
Ami E. Berkowitz*
Affiliation:
General Electric Company, Corporate Research and Development, Schenectady, New York 12301
*
a)Present adress: Center for Magnetic Recording Rescarch, R-001, University of California, San Diego, La Jolla, California 92093.
Get access

Abstract

The microstructure of three different types of γ-Fe2O3 particles were examined using transmission electron microscopy. These included pure γ-Fe2O3, γ-Fe2O3 that had been surface modified using Co, and γ-Fe2O3 that had been doped with Co. The major internal microstructural defects found in the particles in all of the samples were pores and antiphase boundaries. Some particles also had a very high density of dislocations and low-angle boundaries. In general, the particles could be described as single crystals with symmetric cross section. The structure is based on a tetragonal unit cell, and each particle is divided into antiphase domains in which the c axis is oriented at 90°with respect to adjoining domains. The particles often exhibited very irregular shapes. No effect of Co modification was seen on the internal or surface structure of the particles. The Co-doped particles were found to be smaller in size and contained a lower density of internal defects. The effect of the microstructural defects and morphological irregularities in these particles on magnetic behavior is discussed.

Type
Articles
Information
Journal of Materials Research , Volume 1 , Issue 6 , December 1986 , pp. 836 - 844
Copyright
Copyright © Materials Research Society 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1Bate, G., in Ferromagnetic Materials, edited by Wohlfarth, E. P. (North-Holland, New York, 1980), Vol. 2, Chap. 7.Google Scholar
2Aharoni, A., IEEE Trans. Magn. MAG-22, 478 (1986).CrossRefGoogle Scholar
3Berkowitz, A. E., IEEE Trans. Magn. MAG-22, 466 (1986).CrossRefGoogle Scholar
4Sharrock, M. P. and Bodnar, R. E., J. Appl. Phys. 57, 3919 (1985).CrossRefGoogle Scholar
5Ho, H. M., Goo, E. and Thomas, G., J. Appl. Phys. 59, 1606 (1986).CrossRefGoogle Scholar
6Berkowitz, A. E., Goehner, R. P., Hall, E. L., and Flanders, P. J., J. Appl. Phys. 57, 3928 (1985).CrossRefGoogle Scholar
7Kishimoto, M., Amemiya, M. and Hayama, F., IEEE Trans. Magn. MAG-22, 2626 (1985).CrossRefGoogle Scholar
8Koval, K. P., Babkin, E. V., and Pynko, V. G., Phys. Status Solidi A 70, K117 (1982).CrossRefGoogle Scholar
9Babkin, E. V., Koval, K. P., and Pynko, V. G., Sov. Phys. Solid State 25, 332 (1983).Google Scholar