Type III KGd(PO
3)
4 (KGP) and KNd(PO
3)
4 (KNP) inclusion-free single crystals can be grown using the top seededsolution growth-slow cooling
method without pulling even though the viscosity of the solution is high (around 16 Pa·s
-1 near thecrystallization te
mperature). Poisoning by i
mpurities in the crystals was
mini
mized by using the corresponding self-fluxes as solvent.We deter
mined their
main growth process by analyzing the typical
micro
morphologies that appeared on the surface of the as-grownfaces. The crystal
morphologies of KGP and KNP were identified using X-ray diffraction analysis. The external habit of the crystalsappeared to be
more sy
mmetrical than it structurally was because, although KGP and KNP are
monoclinic with space group
P2
1,they have an al
most cubic cell because their cell para
meters are si
milar and the
![](/i<font color=)
mages/gifchars/beta2.gif" BORDER=0 ALIGN="
middle"> angle is very close to 90
![](/i<font color=)
mages/entities/deg.gif">. We checked theche
mical stability of KGP and KNP in basic and acid
media. The distribution and geo
metry of structural defects were studied byanalyzing the etch pits that appeared on the {100}, the {010}, and the {001} for
ms. The crystals cleaved parallel to {010} and{001}, so the surface
micro
morphology of both for
ms was studied. We deter
mined the orientation, the density, and the height of thecleaved planes. We also characterized the local plastic defor
mation of KGP and KNP by
measuring the
microhardness on the {100},{010}, and {001} for
ms using an indentation
method.