ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We use time-resolved spin-polarized photoemission to investigate thermomagnetic writing of domains in magneto-optic media, focusing on the relaxation time of the magnetization and the dynamic behavior of the nucleation process. In our initial studies, we examine a 90-nm-thick GdTbFe film using a pulsed excimer laser (pulse duration: 16 ns) as the light source for the photoemission process. We find that the thermomagnetic switching behavior is different above and below the compensation temperature Tcomp. When the sample temperature is held above Tcomp, the spin polarization of the electrons emitted during the writing pulse has the sign of the initial state even though subsequent examination shows that a reversed magnetization domain has been formed. Therefore, the domain is thermomagnetically nucleated during the trailing edge of the 16 ns writing pulse or even later when the irradiated domain cools down. On the other hand, if the initial temperature is slightly below Tcomp, the electrons emitted during the writing pulse have reversed polarization showing that the reversal of the magnetization takes place quickly compared to the pulse duration. This difference shows that compensation-point writing is much faster than Curie-point writing. Based on these measurements we propose a model to interpret the different thermomagnetic switching processes which take place above and below Tcomp. The results can be explained by different thermal relaxation times between the excited electrons and the lattice and between the electrons and the spin system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.344924
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