Defects in inorganic photorefractive materials and their investigations

14 B. Briat et al.
interchanges of Li and Nb, Nb Li +Li Nb . By probing the crystallographic order
of stoichiometric specimens by EPR and ENDOR, using a low concentration
of Cr 3+ ions as paramagnetic probes, it was demonstrated [12, 48] that such
crystals are really ’regularly’ ordered.
Extrinsic defects in congruent LN:
defect references
defect references
Ti 3+
Li
[16, 49, 50]
Cr 3+
Li
[51, 52, 53, 54] 2Cr 3+
Li
[55]
Mn 2+
Li
[56, 57, 58, 59, 60]
Fe 3+ Li
[57, 61, 60, 62, 63, 64, 65] Fe 2+ Li
[66]
Co 2+
Li
[67, 68, 69]
Ni + Li
[70, 71] Ni 2+
Li
[72]
Cu 2+
Li
[71] Nd 3+
Li
[73, 52]
Gd 3+
?
[74, 75] Tb 4+
?
[76]
Dy 3+
?
[52] Er 3+
?
[77, 52, 78]
Yb 3+
?
[73, 79]
⋆ For Mößbauer studies of Fe see Chapter 5 of this volume
⋆⋆ investigated by thermally detected EPR
Extrinsic defects in congruent LN, co-doped with Mg or Zn:
defect references
Ti 3+
Nb
[80]
[81, 82, 83]
Cr 3+
Nb
Fe 3+
?
[41, 84, 28]
Extrinsic defects in stoichiometric LN:
defect references
Cr 3+
Nb [85]
Fe 3+
?
[64]
Mn 2+
Li
[86]
Tb 3+
?
[76]
Nd 3+
?
[12]
Yb 3+
?
[12, 87]
Table 1. Extrinsic defects in LiNbO 3