Hostname: page-component-745bb68f8f-b6zl4 Total loading time: 0 Render date: 2025-02-05T06:03:20.219Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of Composition and Processing on the Microstructure and Magnetic Properties of 2:17 High Temperature Magnets

Published online by Cambridge University Press:  21 March 2011

W. Tang ,
Y. Zhang ,
D. Goll ,
H. Kronmüller  and
G. C. Hadjipanayis
W. Tang
Affiliation:
University of Delaware, Dept. of Physics & Astronomy, Newark, DE 19716, USA
Y. Zhang
Affiliation:
University of Delaware, Dept. of Physics & Astronomy, Newark, DE 19716, USA
D. Goll
Affiliation:
Max-Planck Institut für Metallforschung, D-70569 Stuttgart, Germany
H. Kronmüller
Affiliation:
Max-Planck Institut für Metallforschung, D-70569 Stuttgart, Germany
G. C. Hadjipanayis
Affiliation:
University of Delaware, Dept. of Physics & Astronomy, Newark, DE 19716, USA
Get access

Abstract

A comprehensive and systematic study has been made on Sm(CobalFevCuyZrx)zmagnets to completely understand the effects of composition and processing on their magnetic properties. The homogenized Sm(Co,Fe,Cu,Zr)z magnets have a featureless microstructure. A cellular/lamellar microstructure develops after 2-3 hours of aging at 800-850°C, but the coercivity increases only after a subsequent slow cooling to 400°C. During cooling, diffusion takes place and Cu is concentrated in the 1:5 cell boundaries and Fe in the 2:17R cells. This dilutes the magnetic properties of the 1:5 phase and causes domain wall pinning/nucleation at the cell boundaries. Higher ratio z leads to larger cells as expected due to the larger amount of the 2:17 phase. For a fixed Cu content, this translates to a larger amount of Cu in the 1:5 cell boundaries, and therefore, to a higher coercivity. Magnets without Cu but with Zr have a lamellar and a cellular like microstructure. In Zr free samples, however, a larger amount of Cu is needed to form the cellular microstructure. This cellular microstructure is unstable with prolonged isothermal aging. A uniform and stable cellular/lamellar microstructure is only observed in alloys containing both Cu and Zr. A higher aging temperature Tag leads to larger cells and higher coercivity as explained above. The results of all these studies clearly show that the amount of Cu in the 1:5 cell boundaries controls both the coercivity and its temperature dependence leading to positive and negative temperature coefficients of coercivity in low and high Cu content alloys, respectively.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 674: Symposia T/U/V – Applications of Ferromagnetic and Optical Materials, Storage and Magnetoelectronics , 2001 , U2.1
Copyright
Copyright © Materials Research Society 2001

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

REFERENCES

1. Ray, A. E. and Liu, S., J. Mater. Eng. Perform, 1, 183(1992).Google Scholar
2. Hadjipanayis, G. C., in Rare earth iron permanent magnets, edited by Coey, J. M. D. (Oxford University Press, Inc., New York, 1996).Google Scholar
3. Ray, A. E., J. Appl. Phys., 55, 2094(1984).Google Scholar
4. Kumar, K., J. Appl. Phys., 63, R13(1988).Google Scholar
5. Fidler, J. and Skalicky, P., J. Magn. Magn. Mater., 30, 58(1982).Google Scholar
6. Mishra, R. K., Thomas, G., Yoneyama, T., Fukino, A., and Ojima, T., J. Appl. Phys. 52, 2517(1981).Google Scholar
7. Rabenberg, L., Mishra, R. K., and Thomas, G., J. Appl. Phys., 53, 2389(1982).10.1063/1.330867Google Scholar
8. Liu, J. F., Chui, T., Dimitar, D., and Hadjipanayis, G. C., Appl. Phys. Lett. 73, 3007(1998).Google Scholar
9. Tang, W., Zhang, Y., and Hadjipanayis, G. C., J. Appl. Phys., 87, 5308(2000).Google Scholar
10. Tang, W., Zhang, Y., and Hadjipanayis, G. C., Appl. Phys. Letter., 77, 421(2001).10.1063/1.126996Google Scholar
11. Liu, J. F., Ding, Y., Zhang, Y., Dimitar, D., Zhang, F., and Hadjipanayis, G. C., J. Appl. Phys., 85, 5660(1999).10.1063/1.369832Google Scholar
12. Cataldo, L., Lefevre, A., Ducret, F., Cohen-Adad, M.-Th., Allibert, C., and Valignat, N., J. Alloys Compd., 241,216(1996).Google Scholar
13. Katter, M., Weber, J., W, Assmus, Schrey, P., and Rodewald, W., IEEE Trans. Magn. 32, 4815(1996).10.1109/20.539161Google Scholar
14. Satyanarayana, M. V., Fujii, H., and Wallace, E., J. Appl. Phys. 53, 2374(1982).Google Scholar
15. Tang, W., Zhang, Y., and Hadjipanayis, G. C., J. Magn. Magn. Mater. 212, 138(2000).10.1016/S0304-8853(99)00783-0Google Scholar
16. Tang, W., Zhang, Y., and Hadjipanayis, G. C., J. Appl. Phys., 87, 399(2000).Google Scholar
17. Liu, S. and Hoffman, E. P., IEEE Trans. Magn., 32, 5091(1996).Google Scholar
18. Chen, C., Walmer, M. S., and Walmer, M. H., J. Appl. Phys., 83, 6706(1998).Google Scholar
19. Liu, J. F., Ding, Y., and Hadjipanayis, G. C., J. Appl. Phys.,85, 1670(1999).10.1063/1.369304Google Scholar
20. Kronmuller, H., in Magnetic hysteresis in novel magnetic materials, NATO ASI Series, 338(1997).Google Scholar
21. Zhang, Y., Tang, W., and Hadjipanayis, G. C., Proceedings of the sixteenth international workshop on rare earth magnets. pp167–177, Sept. 14, 2000, Sendai, Japan.Google Scholar
22. Barbara, B. and Uehara, M., IEEE Trans. Magn., 12, 997(1976).10.1109/TMAG.1976.1059211Google Scholar
23. Deryagin, A. V., J. Physique, 40, 165(1979).Google Scholar
24. Ermolenko, A. S., IEEE Trans. Magn., 12, 992(1976).10.1109/TMAG.1976.1059178Google Scholar
25. Livingston, J. D., J. Appl. Phys., 46, 5259(1975).Google Scholar