Fig. (5)
Excitation spectra of the Ba
3
LaTa
3
O
12
(1), Sr
3
LaTa
3
O
12
(2), Ba
3
LaNb
3
O
12
(3) and Sr
3
LaNb
3
O
12
(4); T = 8 K, E
reg
= 2.9 (left) and 2.4 eV (right).