Critical thickness for ferroelectricity and magnetoelectric effect in multiferroic tunnel junction with symmetrical and asymmetrical electrodesD. Cao, B. Liu, H.L. Yu, W.Y. Hu and M.Q. CaiEur. Phys. J. B, 86 12 (2013) 504DOI: https://doi.org/10.1140/epjb/e2013-40716-8