... Phys. 1 967 , 18, 175.[9] J. B. Cohen, Ultramicroscopy 1990, 34, 41.[10] S. Ino, J. Phys. Soc. Japan 1 966 , 21, 3 46; S. Ino and D. Ogawa, J. Phys. Soc. Japan 1 967 , 22, 1 365 ; J.G. Allpress and J. ... H.Tolentino for stimulating discussions. DZ and DU are indebted to FAPESP (Con-tracts 96/ 12550±8, 97/042 36- 4) and CNPq for funding. BDH gratefully acknowledgesfinancial support for travel under ... Phys. Soc. Jpn. 1 969 , 26, 1559; S. Ino, J. Phys. Soc. Jpn. 1 969 , 27, 941.[15] B. G. Bagley, Nature 1 965 , 208, 67 4.[ 16] C. Y. Yang, J. Cryst. Growth 1979, 47, 274.[17] J. W. Lee and G. D. Stein,...