Magnesium Aluminate (MgAl2O4 or spinel) single crystalsare widely
used for bulk acoustic wave and microwave devices and fast IC
epitaxial substrates. MgAl2O4 is an attractive material for uses in
a wide range of optical, electronic and structural applications
including windows and lenses, which require excellent transmission
from the visible through to the mid IR.
Theoretical transmission is very uniform and approaches 87% between
0.3 to 5 microns. Transmission characteristics rival that of ALON
and sapphire in the mid-wave IR, making it especially attractive
for the ever-increasing performance requirements of current and
next-generation IR imaging systems.
It is also found that MgAl2O4 is a good substrate for III-V
nitrides device. Spinel (MgAl2O4) is one candidate for such GaN LDs
substrate. The crystallographic structure of MgAl2O4 is a spinel
type (Fd3m), and its lattice constant is 8.083 A. MgAl2O4 is a
relatively low-cost substrate material, which has been successfully
applied to the growth of high quality GaN films.
MgAl2O4 is cleaved on the (100) plane. GaN LD cavities have been
obtained by simply cleaving MgAl2O4 substrates along the (100)
direction, which will also work well for ZnO. MgAl2O4 crystal is
very difficult to grow, due to the difficulty in maintaining a
single phase structure.
- good optical, chemical and thermal properties
- good high temperature properties
- stable physical performance
 or  or < ±0.5°
Physical and chemicalcharacteristics
Thermalconductivity at 25°C, W x cm-1 x °K-1
6500 m/s at (100) shear wave