Estimation of the degree of crystallographic ordering of magnetoactive ions in Sr2FeMoO6-δ by means of the intensity of the X-ray peak (101)

Strontium ferromolybdate (Sr₂FeMoO_6-δ, SFMO) having a double Perovskite structure shows good promise as a basic material for spintronics. However SFMO has not yet found wide application due to the low reproducibility of its magnetic properties which partially originates from their strong dependence on the ordering degree of Fe and Mo ions in the B´ and B² sublattices of double perovskite A₂B´B²O₆. We have considered a rapid method of determining strontium ferromolybdate disorder degree. Sublattice population with Fe and Mo ions has been estimated for stoichiometric and nonstoichiometric Sr₂FeMoO_6-δ with a 5% Fe and Mo excess, respectively. We have calculated the intensity ratio between the superstructural ordering (101) peak and the most intense (112 + 200) peak. The calculated curves have been fitted to the analytical expression for similar cases known from literature. The calculation results obtained using this method are in agreement with the results of experimental data processing using the Rietveld method accurate to within ±25 %. Thus this method can be used instead of the Rietveld method if the exposure time set in an X-ray diffraction experiment is insufficient. We have discussed the dependence of the I(101)/I(112 + 200) peak intensity ratio on various factors including diffraction peak instrumental broadening, peak twinning due to grain size reduction, thin film lattice parameter variation due to substrate lattice mismatch and lattice parameter variation due to oxygen vacancies. The method is useful as it allows evaluating the superlattice ordering degree in Sr₂FeMoO_6-d without large time consumption for X-ray diffraction pattern recording and processing with the Rietveld method which may be essential when dealing with large amounts of experimental data

strontium ferromolybdate, atomic ordering degree, X-ray structural analysis

1. Serrate D., De Teresa J. M., Ibarra M. R. Double perovskites with ferromagnetism above room temperature. J. Phys.: Condens. Matter, 2006, vol. 19, no. 2, p. 023201 (86pp). DOI: 10.1088/0953-8984/19/2/023201

2. Kobayashi K.-I., Kimura T., Sawada H., Terakura K., Tokura Y. Room-temperature magnetoresistance in an oxide material with an ordered double-perovskite structure. Nature, 1998, vol. 395, pp. 677—680. DOI: 10.1038/27167

3. Tomioka Y., Okuda T., Okimoto Y., Kumai R., Kobayashi K.-I., Tokura Y. Magnetic and electronic properties of a single crystal of ordered double perovskite Sr2FeMoO6. Phys. Rev. B, 2000, vol. 61, no. 1, pp. 422—427. DOI: 10.1103/PhysRevB.61.422

4. Retuerto M., Alonso J. A., Martínez-Lope M. J., Martínez J. L., García-Hernández M. Record saturation magnetization, Curie temperature, and magnetoresistance in double perovskite synthesized by wet-chemistry techniques. Appl. Phys. Lett., 2004, vol. 85, no. 2, pp. 266—268. DOI: 10.1063/1.1772857

5. Suchaneck G., Kalanda N., Artsiukh E., Gerlach G. Challenges in Sr2FeMoO6 thin film deposition. Phys. Status Solidi (b), 2019, vol. 257, no. 3, p. 1900312. DOI: 10.1002/pssb.201900312

6. Balcells Ll., Navarro J., Bibes M., Roig A., Martı́nez B., Fontcuberta J. Cationic ordering control of magnetization in Sr2FeMoO6 double perovskite. Appl. Phys. Lett., 2001, vol. 78, pp. 781—783. DOI: 10.1063/1.1346624

7. Harnagea L., Berthet P. The effect of strontium non-stoichiometry on the physical properties of double perovskite Sr2FeMoO6. J. Solid State Chem., 2015, vol. 222, pp. 115—122. DOI: 10.1016/j.jssc.2014.11.017

8. Fix T. Couches minces de Sr2FeMoO6 élaborées par ablation laser pour des jonctions tunnel magnétiques. Diss. Dr. Sci. (Phys.-Math.), Strasbourg, 2006.

9. Park B. J., Han H., Kim J., Kim Y. J., Kim C. S., Lee B. W. Correlation between anti-site disorder and magnetic properties in ordered perovskite Sr2FeMoO6. J. Magnetism and Magnetic Materials, 2004, vol. 272, no. 3, pp. 1851—1852. DOI: 10.1016/j.jmmm.2003.12.429

10. Moritomo Y., Shimamoto N., Xu S., Machida A., Nishibori E., Takata M., Sakata M., Nakamura A. Effects of B-site disorder in Sr2FeMoO6 with double perovskite structure. Jpn. J. Appl. Phys., 2001, vol. 40, pt 2, no. 7A, pp. L672— L674. DOI: 10.1143/JJAP.40.L672

11. Mishra R., Restrepo O. D., Woodward P. M., Windl W. First-principles study of defective and nonstoichiometric Sr2FeMoO6. Chemistry of Materials, 2010, vol. 22, no. 22, pp. 6092—6102. DOI: 10.1021/cm101587e

12. Kalanda M., Suchaneck G., Saad A., Demyanov S., Gerlach G. Influence of oxygen stoichiometry and cation ordering on magnetoresistive properties of Sr2FeMoO6±δ. Materials Science Forum, 2010, vol. 636–637, pp. 338—343. DOI: 10.4028/www.scientific.net/MSF.636-637.338

13. Momma K., Izumi F. VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data. J. Appl. Cryst., 2011, vol. 44, pp. 1272—1276. DOI: 10.1107/S0021889811038970

14. Saloaro M., Deniz H., Huhtinen H., Palonen H., Majumdar S., Paturi P. The predominance of substrate induced defects in magnetic properties of Sr2FeMoO6 thin films. J. Phys.: Condens. Matter, 2015, vol. 27, p. 386001 (11pp). DOI: 10.1088/0953-8984/27/38/386001

15. Kircheisen R., Töpfer J. Nonstoichiometry. Point defects and magnetic properties in Sr2FeMoO6-δ double perovskites. J. Solid State Chem., 2015. vol. 185, pp. 76—81. DOI: 10.1016/j.jssc.2011.10.043

16. Wang J.-F., Li Z., Xu X.-J., Gu Z.-B., Yuan G.-L., Zhang S.-T. The competitive and combining effects of grain boundary and Fe/Mo antisite defects on the low-field magnetoresistance in Sr2FeMoO6. J. American Ceramic Society, 2014, vol. 97, pp. 1137—1142. DOI: 10.1111/jace.12749

17. Kuepper K., Balasz I., Hesse H., Winiarski A., Prince K. C., Matteucci M., Wett D., Szargan R., Burzo E., Neumann M. Electronic and magnetic properties of highly ordered Sr2FeMoO6. Phys. Status Solidi (a), 2004, vol. 201, no. 15, pp. 3252—3256. DOI: 10.1002/pssa.200405432

18. Sui Y., Wang X. J., Qian Z. N., Cheng J. G., Liu Z. G., Miao J. P., Li Y., Su W. H., Ong C. K. Enhancement of low-field magnetoresistance in polycrystalline Sr2FeMoO6 with doping. Appl. Phys. Lett., 2004, vol. 85, no. 2, pp. 269—271. DOI: 10.1063/1.1769581

19. Sarma D. D., Ray S., Tanaka K., Kobayashi A., Fujimori A., Sanyal P., Krishnamurthy H. R., Dasgupta C. Intergranular magnetoresistance in Sr2FeMoO6 from a magnetic tunnel barrier mechanism across grain boundaries. Phys. Rev. Lett., 2007, vol. 98, p. 157205 (4pp). DOI: 10.1103/PhysRevLett.98.157205

20. Hayes J. R., Grosvenor A. P. An investigation of the Fe and Mo oxidation states in Sr2Fe2-xMoxO6 (0.25 < x < 1.0) double perovskites by X-ray absorption spectroscopy. J. Alloys and Compounds, 2012, vol. 537, pp. 323—331. DOI: 10.1016/j.jallcom.2012.05.056

21. Spiess L., Teichert G., Schwarzer R., Behnken H., Genzel C. Moderne Röntgenbeugung: Röntgendiffraktometrie für Materialwissenschaftler, Physiker und Chemiker. Berlin; Heidelberg; Wiesbaden: Springer Spektrum, 2019. 624 p. DOI: 10.1007/978-3-8348-8232-5

22. Izumi F., Momma K. Three-dimensional visualization in powder diffraction. Solid State Phenomena, 2007, vol. 130, pp. 15—20. DOI: 10.4028/www.scientific.net/SSP.130.15

23. Adeagbo W. A., Hoffmann M., Ernst A., Hergert W., Saloaro M., Paturi P., Kokko K. Tuning the probability of defect formation via substrate strains in Sr2FeMoO6 films. Phys. Rev. Mater., 2018, vol. 2, no. 8, p. 083604 (9pp). DOI: 10.1103/PhysRevMaterials.2.083604

24. Liu G. Y., Rao G. H., Feng X. M., Yang H. F., Ouyang Z. W., Liu W. F., Liang J. K. Atomic ordering and magnetic properties of non-stoichiometric double-perovskite Sr2FexMo2-xO6. J. Phys.: Condens. Matter, 2003, vol. 15, no. 12, pp. 2053—2060. DOI: 10.1088/0953-8984/15/12/322

25. Sánchez D., Alonso J. A., García-Hernández M., Martínez-Lope M. J., Martínez J. L., Mellergård A. Origin of neutron magnetic scattering in antisite-disordered Sr2FeMoO6 double perovskites. Phys. Rev. B, 2002, vol. 65, no. 10, p. 104426 (8pp). DOI: 10.1103/PhysRevB.65.104426

26. Navarro J., Frontera C., Rubi D., Mestres N., Fontcuberta J. Aging of Sr2FeMoO6 and related oxides. Materials Research Bulletin, 2003, vol. 38, no. 9–10, pp. 1477—1486. DOI: 10.1016/S0025-5408(03)00171-5

27. Huang Y. H., Karppinen M., Yamauchi H., Goodenough J. B. Systematic studies on effects of cationic ordering on structural and magnetic properties in Sr2FeMoO6. Phys. Rev. B, 2006, vol. 73, no. 10, p. 104408 (5pp). DOI: 10.1103/PhysRevB.73.104408

28. Hu Y. C., Ge J. J., Ji Q., Lv B., Wu X. S., Cheng G. F. Synthesis and crystal structure of double-perovskite compound Sr2FeMoO6. Powder Diffraction, 2010, vol. 25, pp. S17—S21. DOI: 10.1154/1.3478711

29. Zhang Q., Xu Z. F., Wang L. F., Gao S. H., Yuan S. J. Structural and electromagnetic properties driven by oxygen vacancy in Sr2FeMoO6-δ double perovskite. J. Alloys and Compounds, 2015, vol. 649, pp. 1151—1155. DOI: 10.1016/j.jallcom.2015.07.211

30. Lü M., Li J., Hao X., Yang Z., Zhou D., Meng J. Hole doping double perovskites Sr2FeMo1-xO6 (x = 0, 0.03, 0.04, 0.06) and their Mössbauer, crystal structure and magnetic properties. J. Phys.: Condens. Matter, 2008, vol. 20, no. 17, p. 175213 (9pp). DOI: 10.1088/0953-8984/20/17/175213

31. Kumar N., Gaur A., Kotnala R. K. Stable Fe deficient Sr2Fe1-δMoO6 (0.0 < δ < 0.10) compound. J. Alloys and Compounds, 2014, vol. 601, pp. 245—250. DOI: 10.1016/j.jallcom.2014.02.173

32. Wang J.-F., Zhang J., Hu B., Gu Z.-B., Zhang S.-T. Tunable low-field magnetoresistance in Sr2FeMoO6 ceramics using organic glycerin to modify grain boundaries and Fe/Mo ordering. J. Phys. D: Appl. Phys., 2014, vol. 47, no. 44, p. 445003 (5pp). DOI: 10.1088/0022-3727/47/44/445003

33. Black D. R., Windover D., Henins A., Gil D., Filliben J., Cline J. P. Certification of NIST standard reference material 640d. Power Diffraction, 2010, vol. 25, no. 2, pp. 187—190. DOI: 10.1154/1.3409482

34. Jalili H., Heinig N. F., Leung K. T. Growth evolution of laser-ablated Sr2FeMoO6 nanostructured films: Effects of substrate-induced strain on the surface morphology and film quality. J. Chem. Phys., 2010, vol. 132, p. 204701 (7pp). DOI: 10.1063/1.3407453

35. Agata S., Moritomo Y., Machida A., Kato K., Nakamura A. Oxidization control of transport properties of Sr2FeMoO6+δ film. Jpn. J. Appl. Phys., 2002, vol. 41, pp. L688—L 690. DOI: 10.1143/JJAP.41.L688

36. Kalanda N., Turchenko V., Karpinsky D., Demyanov S., Yarmolich M., Balasoiu M., Lupu N., Tyutyunnikov S., Sobolev N. A. The role of the Fe/Mo cations ordering degree and oxygen non-stoichiometry on the formation of the crystalline and magnetic structure of Sr2FeMoO6-δ. Phys. Status Solidi B, 2018, vol. 256, p. 1800278 (7pp). DOI: 10.1002/pssb.201800278