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Study of the Low Field Microwave Response in Yttrium Aluminates Dilutely Doped with Manganese

Published online by Cambridge University Press:  10 February 2011

Rakhim R. Rakhimov ,
David E. Jones  and
George B. Loutts
Rakhim R. Rakhimov
Affiliation:
Center for Materials Research, Norfolk State University, Norfolk, VA 23504, U.S.A
David E. Jones
Affiliation:
Center for Materials Research, Norfolk State University, Norfolk, VA 23504, U.S.A
George B. Loutts
Affiliation:
Center for Materials Research, Norfolk State University, Norfolk, VA 23504, U.S.A
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Abstract

Microwave response near zero magnetic field was observed in YAlO3 and CaYAlO4 crystals dilutely doped with Mn in concentration ranging from 0.05 to 2 atomic %. The response is due to non-resonant microwave absorption, which co-exists with normal electron paramagnetic resonance (EPR) absorption due to different paramagnetic valence states of manganese. Mn2+ and Mn4+ charge states were identified in Mn-doped YAlO3, and Mn2+, Mn4+ and Mn5+ in Mn-doped CaYAlO4. The low field response has the opposite phase with respect to the paramagnetic absorption. This shows that Mn-doped YAlO3 and CaYAlO4 exhibit magnetically induced microwave absorption, which has a minimum at zero magnetic field and increases with the applied magnetic field. This effect is similar to microwave magneto-resistance effects observed in manganite perovskites, where spin-dependent electron tunneling occurs between ferromagnetically coupled manganese ions in different valence states. We show, however, that in the present case of diluted paramagnetic systems, magneto-induced microwave losses are due to intramolecular spin-dependent tunneling, where central paramagnetic ion does not change its charge state and spin-dependent charge migration occurs in the first coordination sphere of paramagnetic ion. Evidences are presented that this ion is Mn2+ exhibiting the highest electron spin S = 5/2.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 746: Symposia Q/R – Magnetoelectronics-Novel Magnetic Phenomena in Nanostructures – Advanced Characterization of Artificially Structured Magnetic Materials , 2002 , Q5.9
Copyright
Copyright © Materials Research Society 2003

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References

REFERENCES

1. Cho, S.-Y., Kim, I.-T., and Hong, K. S., J. Mater. Res. 14, 114 (1999).Google Scholar
2. Loutts, G. B., Warren, M., Taylor, L., Rakhimov, R. R., Ries, H. R., Miller, G., Noginov, M. A., Curley, M., Noginova, N., Kukhtarev, N., Caulfield, H. J., and Venkateswarlu, P., Phys. Rev. B, 57, 3706 (1998).Google Scholar
3. Lofland, S. E., Bhagat, S. M., Tyagi, S. D., Mukovskii, Y. M., Karabashev, S. G., and Balbashov, A. M., J. Appl. Phys. 80, 3592 (1996).Google Scholar
4. Srinivasu, V. V., Lofland, S. E., and Bhagat, S. M., J. Appl. Phys. 83, 2866 (1998).Google Scholar
5. von Helmholt, R., Wecker, J., Holzapfel, B., Schultz, L., and Samwer, K., Phys. Rev. Lett. 71, 2331 (1993).Google Scholar
6. Chahara, K., Ohno, T., Kasai, M., and Kozono, Y., Appl. Phys. Lett. 63, 1990 (1993).Google Scholar
7. Hwang, H. Y., Cheong, S.-W., Ong, N. P., and Batlogg, B., Phys. Rev. Lett. 77, 2041 (1996).Google Scholar
8. Rakhimov, R. R., Wilkerson, A. L., Loutts, G. B., Noginov, M. A., Noginova, N., Lindsay, W., and Ries, H. R., Solid State Commun., 108, 549 (1998).Google Scholar
9. Noginov, M. A., and Loutts, G.B., J. Opt. Soc. Am. B, 16, 3 (1999).Google Scholar
10. Noginov, M. A., Loutts, G.B., and Warren, M., J. Opt. Soc. Am. B, 16, 475 (1999).Google Scholar
11. Weil, J. A.; Bolton, J. R.; Wertz, J. E. Electron Paramagnetic Resonance: Elementary Theory and Practical Applications, John Wiley & Sons: New York, 1994.Google Scholar
12. Woensdregt, C. F., Janssen, H. W. M., Gloubokov, A., and Pajaczkowska, A., J. Cryst. Growth, 171, 392 (1997).Google Scholar
13. Anderson, P. W., and Hasegawa, H., Phys. Rev. 100, 675 (1955).Google Scholar