ELEG 667–016; MSEG-667-016 - Solid State Nanoelectronics – Fall 2005 Solutions Homework #5 - due Tuesday, 17 October 2005, in class 1. The maximum demagnetization field in a Néel wall is –4 πMs, (in cgs units) and the maximum self-energy density is ()ss14 MM2π. In a wall of thickness Na, where ais the lattice constant, the demagnetization contribution to the surface energy is 2demags2 MNa.σ≈πThis is a type of anisotropy energy. The total wall energy, exchange + demag, is ()()2222wsJSNa2 MNa ,σ≈ π+πby use of (σw= σex+ σanis). The minimum is at 22222ws1 2223sN0JSN a2 M a, or1NJSM a,2∂σ∂== −π+π=πand is given by ()()()()1 21 23482wsM S 2J a1010101010 erg cm ,−−σ≈ ππ≈
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Centimetre gram second system of units, ERG, maximum demagnetization field, thickness Na, Solid State Nanoelectronics