Effects of the spin-triplet states mixture and electron-phonon coupling in Y3Al5O12:Cr4+ M. G. Brik, N. M. Avram, C. N. Avram and I. Tanaka Eur. Phys. J. Appl. Phys., 29 3 (2005) 239-245 Published online: 21 December 2004 DOI: 10.1051/epjap:2004221