83rd Magnetic Materials Center Seminar
August 6, 2008, 9:00-
7th floor small seminar room, Sengen
Spin polarization of materials with low magnetic moment and large hard axis anisotropy.
A. Rajanikanth
Highly spin polarized materials are necessary for the spintronic devices. At present Heusler alloys are the potential materials which can meet this purpose. On the other hand some of the newly proposed spintronics devices such as domain wall swictching memory need highly spin polarized materials, as well as high perpendicular anisotropy. Heusler alloys have high spin polarization but lack of perpendicular anisotropy, hence there is a need to search for new materials, in this aspect I will present some of my recent experimental and simulated results.

Structural and magnetic properties of Co2FeAl0.5Si0.5 thin films prepared on MgO-buffered Si/SiO2 substrates and TMR using their electrodes
W. H. Wang
Here I will report on the structural and magnetic properties of Co2FeAl0.5Si0.5 (CFAS) thin films deposited on MgO-buffered Si/SiO2 substrates by sputtering. It was found that highly (001) oriented B2-ordered polycrystalline CFAS films can be obtained when annealed below 540 C. In addition, the fabricated CFAS/MgO/CFAS magnetic tunnel junctions (MTJs) exhibited 125% tunneling magnetoresistance (TMR) at room temperature and 196% at 7 K. We proposed that the large TMR observed in this work is due to the high spin polarization of B2-ordered CFAS electrodes, and the coherent tunneling contribution is negligible.

CPP-GMR of multilayered films using Co2MnSi Heusler alloys
K. Kodama
CPP-GMR is necessary to realize the hard disk reading heads for the high recording density medias. But GMR values that have been reported are still small. I prepared CPP-GMR films including the CMS/Cu/CMS layers. This samples showed 8.6% MR ratio at R.T. and 30% at 6 K. This values are higher than reported MR values.