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Ferromagnetic Ordering at Room Temperature in ZnO:Co Nanoparticles

Published online by Cambridge University Press:  01 February 2011

Sujeet Chaudhary
Affiliation:
sujeetc@physics.iitd.ac.in, Indian Institute of Technology Delhi, Department of Physics, Hauz Khas, New Delhi, 110016, India
Kanwal Preet Bhatti
Affiliation:
bhattipkanwal@rediffmail.com, Indian Institute of Technology Delhi, Department of Physics, Hauz Khas, New Delhi, 110016, India
Shankhmala Kundu
Affiliation:
shankhamalakundu@yahoo.co.in, Indian Institute of Technology Delhi, Department of Physics, Hauz Khas, New Delhi, 110016, India
Subhash C. Kashyap
Affiliation:
skashyap@physic.iitd.ac.in, Indian Institute of Technology Delhi, Department of Physics, Hauz Khas, New Delhi, 110016, India
Dinesh K. Pandya
Affiliation:
dkpandya@physics.iitd.ac.in, Indian Institute of Technology Delhi, Department of Physics, Hauz Khas, New Delhi, 110016, India
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Abstract

Intrinsic room temperature ferromagnetism is reported in sequentially sintered (in air ambient) nanocrystalline ZnO:Co (1 to 10 at% Co) samples prepared by chemical route. The Curie temperature of the ZnO:Co ferromagnetic samples is determined to be ∼495°C. The saturation magnetization of the ferromagnetic phase is found to first increase with Co concentration (up to 5%) and then decrease. It is also found to decrease with increase in sintering temperature up to 800°C; there after it remains unaffected till 1000°C. The d-d band transitions in the optical spectrum confirm that Co2+ substitutes Zn2+ in the ZnO lattice. A plausible explanation of the observed ferromagnetic ordering is presented in terms of Bound Magnetic Polarons model.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

[1] Kolesnik, S., Dabrowski, B., and Mais, J., J. Appl. Phys. 95, 2582 (2004).Google Scholar
[2] Lin, H., Chin, T. S., Shih, J. C., Lin, S. H., Hong, T. M.. Huang, R. T., Chen, F. R. and Kai, J. J., Appl. Phys. Lett. 85, 621 (2004).Google Scholar
[3] Wang, Y., Sun, L., Kong, L. G., Kang, J. F., Zhang, X. and Han, R., J. of Alloys and Compounds 423, 256 (2006)Google Scholar
[4] Manivannan, A., Dutta, P., Glaspell, G. and Seehra, M. S., J. Appl. Phys. 99, 08M110 (2006).Google Scholar
[5] Lommens, P., Smet, P. F., Donega, C. M., Maijerink, A., Piraux, L., Michotte, S., Tempfli, S. M., Poelman, D. and Hens, Z., J. Lumin. 118, 245 (2006).Google Scholar
[6] Ozerov, I., Chabre, F. and Marine, W., Mat. Sci. and Engg. B 25, 614 (2005).Google Scholar
[7] Schwartz, D. A. and Gamelin, D. R., Adv. Mater. 16 2115 (2005).Google Scholar
[8] Maensiri, S., Laokul, P., Phokha, S., J. Magn. Magn. Matr. 305 381 (2006).Google Scholar
[9] Martinez, B., Sandiumenge, F., Balcells, L., Aribol, J., Sibieude, F. and Monty, C., Phys. Rev. B 72, 165202 (2005).Google Scholar
[10] Garcia, M. A., Gonzalez, M. L. R., Quesada, A., Kramer, J. L. C., Fernandez, J. F., Khatib, S. J., Wennberg, A., Caballero, A. C., Gonzalez, M. S. M., Villegas, M., Calbet, J. M. G. and Hernando, A., Phys. Rev. Lett. 94, 217206 (2005).Google Scholar
[11] Kim, J. H., Kim, H., Kim, D., Ihm, Y. E. and Choo, W. K., J. Appl. Phys. 92, 6066 (2002).Google Scholar
[12] Deka, S. and Joy, P. A., Appl. Phys. Lett. 89 032508 (2006).Google Scholar
[13] Kaminski, A. and Sarma, S. D., Phys. Rev. Lett. 88, 247202 (2002).Google Scholar
[14] Coey, J. M. D., Venkatesan, M. and Fitzgerald, C.B., Nat. Mater. 4, 173 (2005).Google Scholar
[15] Song, C. et al., Phys. Rev. B 73, 024405 (2006).Google Scholar