CRYSTAL GROWTH AND OPTICAL PROPERTIES OF LaMgAl11O19 : Cr, Nd C. WYON, J.J. AUBERT, D. VIVIEN and A.M. LEJUS J. Phys. Colloques, 48 C7 (1987) C7-483-C7-487 DOI: 10.1051/jphyscol:19877115