69th Magnetic Materials Center Seminar
February 29, 2008, 9:00-
8th floor middle seminar room, Sengen
3DAP analysis of Diluted Magnetic Semiconductors (Ga,Mn)As
M. Kodzuka
Diluted magnetic semiconductors (DMSs) are very attractive materials, because they show both ferromagnetism and compatibility with existing III-V based technology. In the case of (Ga,Mn)As, it is well known that the magnetic properties depend on the concentration of Mn. Thus, it is very important to find out the distribution of Mn in (Ga,Mn)As. So, I performed the 3DAP measurement of (Ga,Mn)As and got the atom maps. In my presentation, the background of this study and the analysis results of the atom maps will been shown.


B. S. Rao


Promising material for a highly spin polarized current source: Co2FeGa0.25Si0.75
T. Nakatani
As a spin polarized current source ferromagnetic materials are required to high spin polarization at room temperature. Therefore it is crucial for them to posses high Curie temperature and high tolerance of disordering (to maintain high P even with disorder). A quaternary Heusler alloy Co2FeGa0.25Si0.75 has been proposed by an ab-initio calculations assuming the perfect ordered and partially disordered structures by Dr. Zsolt Gercsi at MMC. According to them this alloys has its Fermi level at the center of the gap and high spin polarization stability against disordering. Moreover past experimental works reported that both Co2FeGa and Co2FeSi alloys have the highest Curie temperature (1100 K) among Heusler alloys and show L21 ordering easily. Thus it is expected that the quaternary alloy also have high Curie temperature and order to L21 phase even in thin films.
In this seminar presentation I show experimental results in the points of structure, magnetization and spin polarization for bulk sample and talk about future research plan.