Soft-magnetic properties of compositionally modulated Fe/Al films

Abstract

Soft-magnetic properties of Fe/Al compositionally modulated multilayer films prepared in the low argon pressure of 2 mTorr with double target dc magnetron sputtering have been studied. Characteristic x-ray diffraction peaks corresponding to artificial structure on [Fe(4–50 Å)/Al(8 Å)]150 multilayer films were observed. Maintaining a constant Al layer thickness of 8 Å, the coercivity in the hard axis rapidly decreases from 50 Oe to <1 Oe as the Fe layer thickness increases from 4 to 24 Å. When the Fe/Al thickness ratio is around 3, minimum coercivity was obtained. In the region of bilayer thickness ratio δFe/δAl < 3.0, the Ms per Fe unit volume decreases with decreasing δFe/δAl. The higher resistivity was obtained in the films of δFe/δAl < 3.0, and resistivity decreases as δFe/δAl increases. The internal film stress also decreases as δFe/δAl increases. The [Fe(20 Å)/Al(8 Å)]150 multilayer film exhibited a low coercivity 0.5 Oe, a high saturation magnetization 1210 emu/cm3, and a high resistivity 119 μΩ cm.