Spin dephasing in the excited triplet state of F+ -center pairs in CaO

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Spin dephasing in the excited triplet state of F+ -center pairs in CaO

R. Hond, M. Glasbeek

To cite this version:

R. Hond, M. Glasbeek. Spin dephasing in the excited triplet state of F+ -center pairs in CaO. Journal

de Physique Colloques, 1980, 41 (C6), pp.C6-540-C6-540. �10.1051/jphyscol:19806142�. �jpa-00220052�

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JOURNAL DE PHYSIQUE Colloque C6, supplkment au no 7 , Tome 41, Juillet 1980, page C6-540

Spin dephasing in the excited triplet state of F+-center pairs in CaO

R.

Hond and

M.

Glasbeek

Laboratory for Physical Chemistry, University of Amsterdam, Nieuwe Achtergracht 127, Amsterdam, The Netherlands

Abstract.

-

Spin coherence decay in the photo-excited 3B, state of exchange-coupled F+-center pairs in CaO is studied utilizing techniques for the optical detection of spin echoes and spin locking. The homogeneous dephasing time is shown to decrease rapidly with increasing (low) magnetic field strengths. The phenomenon arises because H induces a magnetic moment within the triplet spin system and as a result dipolar spin-spin interactions become increasingly important in the dephasing processes. As the temperature is raised from 1.5 K up to 10 K, the spin- echo decay shapes are changed from exponential to Gaussian whereas the dephasing time, TM, is increased from 150 ps up to 300 ps. The results are related to existing spectral diffusion theories.

DISCUSSION

Question. - B.

HENDERSON.

lity you mention : (i) the magnetic field dependence.

Can you be sure that dipolar interactions between of the de~hasing shows that coupling is to S =

3 F:

centres and excited F-centres in triplet states do spins, (ii) optically detected cross relaxation also not contribute to the spin dephasing time. shows that coupling is to

S

⁼

4

centres, (iii) F+-centres are abundant, whereas compared to this the concen- Reply.

-

M .

GLASBEEK.

tration of photo-excited F-centres is negligible.

For a number of reasons we can neglect the possibi-

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19806142