حساب زهن الاسترخاء لوسائط التسجيل المغناطيسي الطولي والعمودي

In this paper we Calculate relaxation time for longitudinal and perpendicular magnetic recording media, respectively as a function of normalized applied field f0 and attempt frequency o f at different value of the thermal stability factor r= 20,40,60,100, where, a small values of r lead to thermal unstable, while large values lead to thermal stable. In experiment results, the attempt frequency is often taken as constant, but in this research we used attempt frequency as the function of the temperature, applied field, volume grain and the damping constant. f0 can be calculated from Fokker-Planck equation (FPE). We have found that the attempt frequency is typically about 10 HZ 11 and 10 HZ 10 for longitudinal recording and perpendicular recording, respectively, which is much larger than the commonly used estimate of 10 HZ 9 .