1. Burns, G. & Dacol, F. H. Glassy polarization behavior in ferroelectric compounds Pb(Mg 1/3 Nb 2/3 )O 3 and Pb(Zn 1/3 Nb 2/3 )O 3 . Solid State Commun. 48, 853–856 (1983).

2. Xu, G. Probing local polar structures in PZN-xPT and PMN-xPT relaxor ferroelectrics with neutron and x-ray scattering. J. Phys. Conf. Ser. 320, 012081 (2011).

3. Gehring, P. M. Neutron diffuse scattering in lead-based relaxor ferroelectrics and its relationship to the ultra-high piezoelectricity. J. Adv. Dielectr. 2, 1241005 (2012).

4. Westphal, V., Kleeman, W. & Glinchuk, M. D. Diffuse phase transitions and random-field-induced domain states of the ‘relaxor’ ferroelectric PbMg 1/3 Nb 2/3 O 3 . Phys. Rev. Lett. 68, 847–850 (1992).

5. Cowley, R. A., Gvasaliya, S. N., Lushnikov, S. G., Roessli, B. & Rotaru, G. M. Relaxing with relaxors: a review of relaxor ferroelectrics. Adv. Phys. 60, 229–327 (2011).

6. Fu, D. et al. Relaxor Pb(Mg 1/3 Nb 2/3 )O 3 : a ferroelectric with multiple inhomogeneities. Phys. Rev. Lett. 103, 207601 (2009).

7. Ni, Y., Chen, H. T., Shi, Y. P., He, L. H. & Soh, A. K. Modeling of polar nanoregions dynamics on the dielectric response of relaxors. J. Appl. Phys. 113, 224104 (2013).

8. Li, F. et al. The origin of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals. Nat. Commun. 7, 13807 (2016).

9. Li, F., Xu, Z. & Zhang, S. The effect of polar nanoregions on electromechanical properties of relaxor-PbTiO3 crystals: extracting from electric-field-induced polarization and strain behaviors. Appl. Phys. Lett. 105, 122904 (2014).

10. Pirc, R., Blinc, R. & Vikhnin, V. S. Effect of polar nanoregions on giant electrostriction and piezoelectricity in relaxor ferroelectrics. Phys. Rev. B 69, 212105 (2004).

11. Takenaka, H., Grinberg, I., Liu, S. & Rappe, A. M. Slush-like polar structures in single-crystal relaxors. Nature 546, 391–395 (2017).

12. Hlinka, J. Do we need the ether of polar nanoregions? J. Adv. Dielectr. 2, 1241006 (2012).

13. Burton, B. P., Cockayne, E. & Waghmare, U. V. Correlations between nanoscale chemical and polar order in relaxor ferroelectrics and the lengthscale for polar nanoregions. Phys. Rev. B 72, 064113 (2005).

14. Sherrington, D. BZT: a soft pseudospin glass. Phys. Rev. Lett. 111, 227601 (2013).

15. Akbarzadeh, A. R., Prosandeev, S., Walter, E. J., Al-Barakaty, A. & Bellaiche, L. Finite-temperature properties of Ba(Zr,Ti)O 3 relaxors from first principles. Phys. Rev. Lett. 108, 257601 (2012).

16. Phelan, D. et al. Phase diagram of the relaxor ferroelectric (1−x)Pb(Mg 1/3 Nb 2/3 )O 3 -xPbTiO 3 revisited: a neutron powder diffraction study of the relaxor skin effect. Phase Transit. 88, 283–305 (2015).

17. Bonneau, P. et al. X-ray and neutron diffraction studies of the diffuse phase transition in ceramics. J. Solid State Chem. 91, 350–361 (1991).

18. de Mathan, N. et al. A structural model for the relaxor PbMg 1/3 Nb 2/3 O 3 at 5 K. J. Phys. Condens. Matter 3, 8159–8171 (1991).

19. Guo, Y. et al. The phase transition sequence and the location of the morphotropic phase boundary region in (1− x)[Pb(Mg 1/3 Nb 2/3 )O 3 ]–xPbTiO 3 single crystal. J. Phys. Condens. Matter 15, L77 (2003).

20. Bokov, A. A. & Ye, Z. G. Recent progress in relaxor ferroelectrics with perovskite structure. J. Mater. Sci. 41, 31–52 (2006).

21. Grinberg, I., Juhás, P., Davies, P. & Rappe, A. Relationship between local structure and relaxor behavior in perovskite oxides. Phys. Rev. Lett. 99, 267603 (2007).

22. Kutnjak, Z., Petzelt, J. & Blinc, R. The giant electromechanical response in ferroelectric relaxors as a critical phenomenon. Nature 441, 956–959 (2006).

23. Goossens, D. J. Diffuse scattering from lead-containing ferroelectric perovskite oxides. ISRN Mater. Sci. 2013, 107178 (2013).

24. Goossens, D. J. Local ordering in lead-based relaxor ferroelectrics. Acc. Chem. Res. 46, 2597–2606 (2013).

25. Xu, G., Zhong, Z., Hiraka, H. & Shirane, G. Three-dimensional mapping of diffuse scattering in Pb(Zn 1/3 Nb 2/3 )O 3 -xPbTiO 3 . Phys. Rev. B 70, 174109 (2004).

26. Xu, G., Shirane, G., Copley, J. R. D. & Gehring, P. M. Neutron elastic diffuse scattering study of Pb(Mg 1/3 Nb 2/3 )O 3 . Phys. Rev. B 69, 064112 (2004).

27. Hiraka, H., Lee, S.-H., Gehring, P. M., Xu, G. & Shirane, G. Cold neutron study on the diffuse scattering and phonon excitations in the relaxor Pb(Mg 1/3 Nb 2/3 )O 3 . Phys. Rev. B 70, 184105 (2004).

28. Gehring, P. M. et al. Reassessment of the Burns temperature and its relationship to the diffuse scattering, lattice dynamics, and thermal expansion in relaxor Pb(Mg 1/3 Nb 2/3 )O 3 . Phys. Rev. B 79, 224109 (2009).

29. Stock, C. et al. Universal static and dynamic properties of the structural transition in Pb(Zn 1/3 Nb 2/3 )O 3 . Phys. Rev. B 69, 094104 (2004).

30. Paściak, M., Wołcyrz, M. & Pietraszko, A. Interpretation of the diffuse scattering in Pb-based relaxor ferroelectrics in terms of three-dimensional nanodomains of the <110>-directed relative interdomain atomic shifts. Phys. Rev. B 76, 014117 (2007).

31. Vakhrushev, S., Ivanov, A. & Kulda, J. Diffuse neutron scattering in relaxor ferroelectric PbMg 1/3 Nb 2/3 O 3 . Phys. Chem. Chem. Phys. 7, 2340 (2005).

32. Bosak, A., Chernyshov, D., Vakhrushev, S. & Krisch, M. Diffuse scattering in relaxor ferroelectrics: true three-dimensional mapping, experimental artefacts and modelling. Acta Crystallogr. A. 68, 117–123 (2012).

33. Takenaka, H., Grinberg, I. & Rappe, A. M. Anisotropic local correlations and dynamics in a relaxor ferroelectric. Phys. Rev. Lett. 110, 147602 (2013).

34. Phelan, D. et al. Role of random electric fields in relaxors. Proc. Natl Acad. Sci. USA 111, 1754 (2014).

35. Stock, C. et al. Neutron and x-ray diffraction study of cubic [111] field-cooled Pb(Mg 1∕3 Nb 2∕3 )O 3 . Phys. Rev. B 76, 064122 (2007).

36. Tkachuk, A. & Chen, H. Anti-ferrodistortive nanodomains in PMN relaxor. AIP Conf. Proc. 677, 55 (2003).

37. Swainson, I. et al. Soft phonon columns on the edge of the Brillouin zone in the relaxor PbMg 1/3 Nb 2/3 O 3 . Phys. Rev. B 79, 224301 (2009).

38. Hilton, A. D., Barber, D. J., Randall, C. A. & Shrout, T. R. On short range ordering in the perovskite lead magnesium niobate. J. Mater. Sci. 25, 3461–3466 (1990).

39. Xu, G., Zhong, Z., Bing, Y., Ye, Z.-G. & Shirane, G. Electric-field-induced redistribution of polar nano-regions in a relaxor ferroelectric. Nat. Mater. 5, 134–140 (2006).

40. Li, Q. et al. Soft phonon modes and diffuse scattering in Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 relaxor. Preprint at https://arxiv.org/abs/1610.09768 (2016).

41. Pasciak, M. et al. Assessing local structure in PbZn 1/3 Nb 2/3 O 3 using diffuse scattering and reverse Monte Carlo refinement. Metall. Mater. Trans. A 44, 87–93 (2013).

42. Welberry, T. R. et al. Single-crystal neutron diffuse scattering and Monte Carlo study of the relaxor ferroelectric PbZn 1/3 Nb 2/3 O 3 (PZN). J. Appl. Crystallogr. 38, 639–647 (2005).

43. Stock, C. et al. Damped soft phonons and diffuse scattering in 40%Pb(Mg 1/3 Nb 2/3 )O 3 -60%PbTiO 3 . Phys. Rev. B 73, 064107 (2006).

44. Xu, G., Viehland, D., Li, J. F., Gehring, P. M. & Shirane, G. Evidence of decoupled lattice distortion and ferroelectric polarization in the relaxor system PMN-xPT. Phys. Rev. B 68, 212410 (2003).

45. Gehring, P. M., Chen, W., Ye, Z.-G. & Shirane, G. The non-rhombohedral low-temperature structure of PMN-10% PT. J. Phys. Condens. Matter 16, 7113 (2004).

46. Matsuura, M. et al. Composition dependence of the diffuse scattering in the relaxor ferroelectric compound (1 − x)Pb(Mg 1∕ 3 Nb 2∕ 3 )O 3 −xPbTiO 3 (0 ≤ x ≤ 0.40). Phys. Rev. B 74, 144107 (2006).

47. Jin, Y. M., Wang, Y. U. & Khachaturyan, A. G. Conformal miniaturization of domains with low domain-wall energy: monoclinic ferroelectric states near the morphotropic phase boundaries. Phys. Rev. Lett. 91, 197601 (2003).

48. Vakhrushev, S., Nabereznov, A., Sinha, S. K., Feng, Y. P. & Egami, T. Synchrotron X-ray scattering study of lead magnoniobate relaxor ferroelectric crystals. J. Phys. Chem. Solids 57, 1517–1523 (1996).

49. Prosandeev, S. & Bellaiche, L. Effects of atomic short-range order on properties of the PbMg 1/3 Nb 2/3 O 3 relaxor ferroelectric. Phys. Rev. B 94, 180102 (2016). (R).

50. Rosenkranz, S. & Osborn, R. Corelli: efficient single crystal diffraction with elastic discrimination. Pramana J. Phys. 71, 705–711 (2008).

51. Ye, F., Liu, Y., Whitfield, R., Osborn, R. & Rosenkranz, S. Implementation of cross correlation for energy discrimination on the time-of-flight spectrometer CORELLI. J. Appl. Cryst. 51, 315–322 (2018).

52. Arnold, O. et al. Mantid-data analysis and visualization package for neutron scattering and μ SR experiments. Nucl. Instrum. Meth. Phys. Res. A 764, 156–166 (2014).

53. Michels-Clark, T. M., Savici, A. T., Lynch, V. E., Wang, X. & Hoffmann, C. M. Expanding Lorentz and spectrum corrections to large volumes of reciprocal space for single-crystal time-of-flight neutron diffraction. J. Appl. Crystallogr. 49, 497–506 (2016).

54. Crystal Coordinate Transformation Workflow (CCTW). Advanced Photon Source, Argonne National Laboratory (2017); https://www.aps.anl.gov/Science/Scientific-Software/CCTW.