62nd Magnetic Materials Center Seminar
November 16, 2007, 9:00-
7th floor seminar room, Sengen
Effect of various parameters on Magnetoresistance of CoCrFeSi exchage biased spin valves
H. S. Goripati
The aim of my work is to develop CPP-GMR junctions as they are calimed to be the next generation read heads of for high density recording media. In the process we changed many experimental parameters to realise high MR which effected the MR value in different ways. Though the MR values seem to be very low in my case, the effect various parametrs on MR is evident and provide an insight into further improvemnt of the MR. Value. The experimental parameters that were changed are as following:
1) Magnetic Annealing temp.
2) Spacer layer thickness
3) Cap layer thickness and material
4) Free layer thickness
5) Buffer layer thickness.
The obtained results in view of the above parameters will be presented.

Microstructure, magnetic and transport properties of Co ferrite thin film
Y. K. Takahashi
Co-ferrite thin film which is oxidized by the radical oxidation at 400C shows the metallic transport property at RT. This is maybe due to the oxygen deficiency. The oxygen deficiency acts as the hopping site of the electron. To improve the oxygen deficiency, I change the oxidation and annealing condition. In this presentation, I will show the big change in the properties of the Co-ferrite thin film depending on the oxidation and annealing condition.

Coercivity generation of surface Nd2Fe14B grains and state of Cu at the Nd-Cu/Nd2Fe14B interface in Nd-Cu sputtered NdFeB sintered magnets.
T. Fukagawa
(1)Surface coercivity recovered to its full value identical to the coercivity of bulk magnet in a Nd-14at%Cu film/NdFeB ternary sintered magnet after annealing at 375 and 400 ℃.
(2)The grains of fcc structure containing Nd-Cu-O were adjacent to Nd2Fe14B grains in the samples of (1).
(3)(2) were also observed in a NdFeB-0.1mass%Cu sintered magnet.
(4)It is thought that solid solution of Cu into fcc phase decreases the interface energy between grain boundary phase and Nd2Fe14B grains and improves the wet ability and the coercivity.