Studies Of FeCoN Thin Films For Ultra-high Density Magnetic Recording Write-head

Soft magnetic thin films with high saturation magnetization have very high application value in write head materials and high frequency micro-sensor. However,so far,the soft magnetic thin films with high saturation magnetization over than 2.IT and coercivity less than 1 Oe simultaneously are still few.The saturation magnetization of Fe₆₅Co₃₅ films is as high as 2.45T..Doping N into Fe₆₅Co₃₅ films is effective to decrease the coercivity while the saturation magnetization will be decrease.The main contents of this paper are maintaining the high saturation magnetization when the coercivity is effectively decreased,and the preparation of FeCoN thin films with high saturation magnetization as well as low coercivity.The experimental results are as follows:1.As the N partial pressure increase,the grain of FeCoN thin films inflate and the nanocrystal and amorphous composition increase.2.As the N partial pressure increase,the coercivity along easy axis H_ce of FeCoN thin films decrase from 174 Oe to 3 Oe and that along hard axis H_ch decrease from 170 Oe to 0.4 Oe;the saturation magnetization has a slight decrease from maximum 2.45T to minimum 1.15T;the resistance increase from 112μΩ.cm to maximum 249μΩ.cm,and then reduce slowly to 197μΩ.cm.3.When the N partial pressure is 10%,the FeCoN thin films have excellent soft magnetic properties and the BCC phase and amorphousα-Fe(Co,N) coexist.The coercivity are H_ce=4.5 Oe and H_ch=1.3 Oe,the saturation magnetization is Ms=2.02T,the anisotropy field is H_k=90 Oe,the resistance isρ=228μΩ.cm.4.When the N partial pressure increase,the stressσand the magnetostriction constantλ_s both decrease.But the FeCoN thin film with 10%N partial pressure is exceptional.It has the maximal anisotropy field(90 Oe) and the maximal ferromagnetic resonance(FMR) frequency f_r(3.45GHz).5.Two different deposition methods have different influence on structure and soft magnetic properties for FeCoN thin film.In contrast,the method with oblique substrate and N flow to the surface of FeCo target is better than that with horizontal substrate and N flow to the underside of substrate.