Title :
Influence of gas adsorption at the interface on the exchange coupling field of Ni-Fe/25at%Ni-Mn/Ni-Fe films
Author :
Uneyama, K. ; Tsunoda, M. ; Takahashi, M.
Author_Institution :
Precision Technol. Dev. Center, Sharp Corp., Tenri, Japan
fDate :
9/1/1997 12:00:00 AM
Abstract :
The influence of gas adsorption at the interface on the exchange coupling field was investigated for Ni-Fe 200 Å/25at%Ni-Mn 200 Å/Ni-Fe 300 Å trilayer films deposited on Si(100) substrate. When the interface between the lower Ni-Fe layer and the Ni-Mn layer was exposed to an atmosphere with leaking air, 5×10-8~2×10-6 Torr for 60 min, unidirectional anisotropy constant, Jk at the both interfaces abruptly decreased at 1×10-7 Torr of exposed pressure and vanished at 2×10-7 Torr. The vanishing Jk was strongly correlated with disappearance of γ-Ni-Mn phase verified by TEM observation. In order to clarify the gas species which adsorb on the Ni-Fe surface and suppress the formation of γ-Ni-Mn phase on it, the exposure of the interface under various pure gas atmosphere (N2, O2, H2O) was examined. As a result, oxygen was confirmed to be the most probable gas element, and the surface oxidation of Ni-Fe layer was found to prevent the epitaxial growth of γ-Ni-Mn grains on it
Keywords :
adsorption; exchange interactions (electron); ferromagnetic materials; interface magnetism; iron alloys; magnetic anisotropy; magnetic multilayers; manganese alloys; nickel alloys; oxidation; transmission electron microscopy; 1E-7 to 2E-7 torr; 200 A; 300 A; 60 min; H2O; N2; Ni-Fe/Ni-Mn/Ni-Fe films; NiFe-NiMn-NiFe; O2; exchange coupling field; gas adsorption; interface; unidirectional anisotropy constant; Anisotropic magnetoresistance; Atmosphere; Magnetic field measurement; Magnetic films; Magnetic heads; Magnetization; Oxidation; Pumps; Sputtering; Substrates;
Journal_Title :
Magnetics, IEEE Transactions on
