Type III KGd(PO
3)
4 (KGP) and KNd(PO
3)
4 (KNP) inclusion-f
ree single c
rystals can be g
rown using the top seeded
solution g
rowth-slow cooling method without pulling even though the viscosity of the
solution is high (a
round 16 Pa·s
-1 nea
r thec
rystallization tempe
ratu
re). Poisoning by impu
rities in the c
rystals was minimized by using the co
rresponding self-fluxes as
solvent.We dete
rmined thei
r main g
rowth p
rocess by analyzing the typical mic
romo
rphologies that appea
red on the su
rface of the as-g
rownfaces. The c
rystal mo
rphologies of KGP and KNP we
re identified using X-
ray diff
raction analysis. The exte
rnal habit of the c
rystalsappea
red to be mo
re symmet
rical than it st
ructu
rally was because, although KGP and KNP a
re monoclinic with space g
roup
P2
1,they have an almost cubic cell because thei
r cell pa
ramete
rs a
re simila
r and the
rs/beta2.gif" BORDER=0 ALIGN="middle"> angle is ve
ry close to 90
. We checked thechemical stability of KGP and KNP in basic and acid media. The dist
ribution and geomet
ry of st
ructu
ral defects we
re studied byanalyzing the etch pits that appea
red on the {100}, the {010}, and the {001} fo
rms. The c
rystals cleaved pa
rallel to {010} and{001}, so the su
rface mic
romo
rphology of both fo
rms was studied. We dete
rmined the o
rientation, the density, and the height of thecleaved planes. We also cha
racte
rized the local plastic defo
rmation of KGP and KNP by measu
ring the mic
roha
rdness on the {100},{010}, and {001} fo
rms using an indentation method.