Magnetic excitations ferromagnetic films

For a ferromagnetic sensor with an anisotropy of 1.6 kA/m (20 Oe) and a magnetization of 1 T, the eigenfreqnency for the lowest order mode is simply that of Eq.lO, with a characteristic freqnency of 1.3 GHz. Thus, the number of excitations occnpying the lowest order mode at an operational temperatnre of T = 400 K is N(g)) 7000. The nnmber of nnpaired spins in a free layer is proportional to the volnme of the magnetic film (typically 0.18 pm x 0.06 pm = 5 nm = 5.4 x 10 nm ) and the magnetization density of the material. The relative fraction nfco) of spin excitations is therefore... 

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