The luminescence of Mn

4+

ions shows different features for MgAl

2

O

4

ZnAl

2

O

4

and LiAl

5

O

8

which all have a spinel structure. In LiAl

5

O

8

the emission spectrum of Mn

4+

consists of a sharp line at 660nm overlapped on a broad band with maximum at 680nm. The former is assigned to the

2

E→

4

A

2

transition of Mn

4+

and the latter is attributed to the vibronic side band. The emission of Mn

4+

showed a higher intensity in LiAl

5

O

8

and however

only a weak emission was observed in MgAl

2

O

4

and almost no luminescence was recorded in ZnAl

2

O

4

. The differences in the intensity of the Mn

4+

emissions for the three spinel compounds can be illustrated by the fact that the compounds have different micro-structures and composition elements. In the perovskite-related aluminates LaAlO

3

and GdAlO

3

The Mn

4+

ions show 2 and 3 sharp emission lines

respectively

under 254nm excitation at room temperature. The Mn

4+

emission peaks locate at 695 and 725nm for LaAlO

3

:Mn

Ca and at 680

700 and 715nm for GdAlO

3

:Mn

Ca. These lines are assigned to the

2

E→

4

A

2

transition of Mn

4+

ions and its phonon-coupling transitions. Energies of the phonons asso-ciated with the

2

E→

4

A

2

transition have been estimated. Both the excitation spectra of Mn

4+

in LaAlO

3

:Mn

Ca and GdAlO

3

:Mn

Ca show two broad bands. One locates at about 300nm and the other at about 500nm. The strong band at about 300nm is assigned to the O

2-

→Mn

4+

charge-transfer band and the weaker band at about 500nm is due to the

4

A

2

→

4

T

2

transition of Mn

4+

. The

4

A

2

→

4

T

1

absorption transition is almost hidden under the charge-transfer band and exhibits only a little peak or shoulder at about 330nm. From the energy of the

4

A

2

→

4

T

2

transition we estimate crystal field parameter

Dq

to be equal to 2 000cm

-1

for LaAlO

3

:Mn

Ca and 2 040cm

-1

for GdAlO

3

:Mn

Ca.