In ferroelectrics, a significant improvement of stability is achieved with the application of multi-layer interstitial ferroelectric compounds, e.g. (Bi₂O₂)²⁺(A_m−1B_mO_3m+1)²⁻, here A = Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Bi²⁺, or La³⁺ and B = Ti⁴⁺, Ta⁵⁺, or Nb⁵⁺. For instance, for m = 2, Bi₂O₂ layers are alternated with perovskite-like AB₂O₇ layers with double oxygen octahedral units. [1, 2] In this system, because the oxygen ions in the perovskite-like layers are more stable than those in the stacked Bi₂O₂ layers [3], the Bi₂O₂ layers are an oxygen source which compensates for the oxygen vacancies in perovskite-like octahedra. Therefore, the oxygen vacancies that are normally generated in the perovskite-like layers to cause fatigue can easily be exchanged with oxygen ions in the Bi₂O₂ layers [4], resulting in much smaller fatigue.

[1] C.A. Paz de Araujo, J.D. Cuchiaro, L.D. McMillan, M. C. Scott, J. F. Scott: Nature 374, 627 (1995).
[2] T. Sumi, N. Moriwaki, G. Nakane, T. Nakakuma, Y. Judai, Y. Uemoto, Y. Nagano, S. Hayashi, M. Azuma, E. Fujii, S. Katsu, T. Otsuki, L. McMillan, C. A. Paz de Araujo, G. Kano: Tech. Dig. Int. Solid-State Circuits Conf., San Francisco (1994) p. 268.
[3] B.H. Park, S.J. Hyun, S.D. Bu, T.W. Noh, J. Lee, H.-D. Kim, T.H. Kim, W. Jo: Appl. Phys. Lett. 74, 1907 (1999).
[4] O. Auciello, A.R. Krauss, J. Im, D.M. Gruen, E.A. Irene, R.P.H. Chang, G. E. McGuire: Appl. Phys. Lett. 69, 2671 (1996).