R. Kircheisen, J. To¨pfer / Journal of Solid State Chemistry 185 (2012) 76–81
81
was recently proposed based on ab-initio calculations [17]. The
magnetization data in Fig. 10b indicate that Ms is reduced from
the Bundesministerium fu¨r Bildung und Forschung (Germany) is
acknowledged (Grant 03WKF22E).
Ms¼3.5 mB at
The fact that the nearly stoichiometric samples already exhibit a
B is attributed to the presence of a
d¼0 to Ms¼3.1 mB at d¼0.1 (linear fit in Fig. 10b).
reduced magnetization of o4
m
certain level of antisite disorder in these samples. Hence the
magnetization reduction due to defect formation now is defined
References
by 3.5
vacancies only, a Ms¼3.3 would be expected for
observed reduction of Ms is somewhat larger than the predicted
rate of ꢀ2/ . This might be explained by the simultaneous
increase of the cation antisite disorder (ASD) with increasing
concentration of oxygen vacancies , as shown in Fig. 9. However,
it is demonstrated that nonstoichiometry and the formation of
oxygen vacancies is another source for reduced magnetization
values.
m
B–2
d
. If the reduction of Ms would be due to oxygen
[1] K.I. Kobayashi, T. Kimura, H. Sawada, K. Terakura, Y. Tokura, Nature 395
(1998) 677.
[2] L. Balcells, J. Navarro, M. Bibes, A. Roig, B. Martinez, J. Fontcuberta, Appl. Phys.
Lett. 78 (3) (2001) 781.
[3] O. Chmaissem, R. Kruk, B. Dabrowski, D.E. Brown, X. Xiong, S. Kolesnik,
J.D. Jorgensen, C.W. Kimball, Phys. Rev. B 62 (2000) 14197 #.
[4] S. Nakamura, K. Oikawa, J. Phys. Soc. Jpn. 72 (12) (2003) 3123–3127.
[5] J. Linden, T. Yamamoto, M. Karppinen, H. Yamauchi, Appl. Phys. Lett. 76
(2000) 2925.
[6] C. Kapusta, P.C. Riedi, D. Zajac, M. Sikora, J.M. De Teresa, L. Morellon,
M.R. Ibarra, J. Magn. Magn. Mater. 242–245 (2002) 242–245.
[7] T. Shimada, J. Nakamura, T. Motohashi, H. Yamauchi, M. Karpinnen,
Chem. Mater. 15 (2003) 4494.
d
¼0.1, but the
d
d
[8] Y.H. Huang, J. Linden, H. Yamauchi, M. Karppinen, Chem. Mater. 16 (2004)
4337–4342.
4. Conclusions
[9] M. Garcia-Hernandez, J.L. Martinez, M.J. Martinez-Lope, M.T. Casais,
J.A. Alonso, Phys. Rev. Lett. 86 (2001) 2443.
[10] X.Z. Liao, A. Sharma, M. Wei, J.L. MacManus-Driscoll, W. Branford, L. Cohen,
Y. Bugoslavsky, Y.T. Zhu, D. Peterson, Y. Jiang, H. Xu, J. Appl. Phys. 96 (2004)
7747.
The double perovskite Sr2FeMoO6ꢀ (SFMO) is stable only at low
d
oxygen partial pressure, e.g. between ꢀ10.2rlog pO2r ꢀ13.7 at
1200 1C. SFMO exhibits a significant nonstoichiometry
d as measured
by thermogravimety at 1000, 1100, and 1200 1C. At higher pO2 close
to the upper phase boundary SFMO is almost stoichiometric (e.g.
[11] J. MacManus-Driscoll, A. Sharma, Y. Bugoslavsky, W. Branford, L.F. Cohen,
M. Wei, Adv. Mater. 18 (2006) 900.
[12] Y.H. Huang, M. Karppinen, H. Yamauchi, J.B. Goodenough, Phys. Rev. B 73
(2006) 104408.
[13] T. Nakamura, K. Kunihara, Y. Hirose, Mat. Res. Bull. 16 (1981) 321.
[14] J. Rager, M. Zipperle, A. Sharma, J.L. MacManus-Driscoll, J. Am. Ceram. Soc. 87
(2004) 1330.
[15] T. Yamamoto, J. Liimatainen, J. Linden, M. Karppinen, H. Yamauchi, J. Mater.
Chem. 10 (2000) 2342–2345.
d
¼0.006 at 1200 1C and log pO2¼ ꢀ10.2), but
decreasing oxygen partial pressure (e.g.
¼0.085 at 1200 1C and
log pO2¼ ꢀ13.5). The nonstoichiometry is accommodated by oxygen
vacancies. The defect formation enthalpy is
d increases with
d
D
HOV¼25378 kJ/mol.
The oxygen vacancies might be associated to form clusters; this
requires further investigations.
The unit cell volume and the antisite concentration of non-
stoichiometric SFMO increases with increasing oxygen vacancy
concentrations. The saturation magnetization decreases with
This demonstrates that in addition to Fe/Mo antisite disorder
[16] H. Chang, M. Garcia-Hernandez, J.A. Alonso, Appl. Phys. Lett. 89 (2006)
182501.
[17] S. Collis, D. Stoeffler, C. Meny, T. Fix, C. Leuvrey, G. Pourroy, A. Dinia,
P. Panissod, J. Appl. Phys. 98 (2005) 033905.
[18] R. Mishra, O.D. Restrepo, P.M. Woodward, W. Windl, Chem. Mater. 22 (2010)
6092–6102.
d.
[19] J. To¨pfer, R. Kircheisen, S. Barth, J. Appl. Phys. 105 (2009) 07D712.
[20] A. Sharma, J.L. MacManus-Driscoll, W. Branford, Y. Bugoslavsky, L.F. Cohen,
J. Rager, Appl. Phys. Lett. 87 (2005) 112505.
oxygen nonstoichiometry
tization values.
d is another source of reduced magne-
[21] J.A.M. van Rossmalen, E.H.P. Cordfunke, J. Solid Stae. Chem 110 (1994)
113–117.
[22] A. Holt, T. Norby, R. Glenne, Ionics 5 (1999) 434–443.
[23] D. Niebieskikwiat, A. Caneiro, R.D. Sanchez, J. Fontcuberta, Phys. Rev. B 64
(2001) 180406.
[24] S. Vasala, M. Lehtima¨ki, Y.H. Huang, H. Yamauchi, J.B. Goodenough,
M. Karppinen, J. Solid State Chem. 183 (2010) 1007–1012.
Acknowledgments
The authors thank S. Barth (IKTS Hermsdorf, Germany) for the
preparation of the starting SFMO material. Financial support by