From the values of coercivity ([H.sub.c]) and saturation magnetization ([M.sub.s]), the value of the anisotropy constant
[K.sub.1] can be calculated using the following relation:
The external field term describes the contribution of an external electric field [??], where [DELTA][epsilon]e stands for the electric field anisotropy constant
and [[epsilon].sub.0] represents the electrical permittivity constant.
Co/Pt multilayers [7, 8] and [L1.sub.0] [CrPt.sub.3] films  with an uniaxial magnetocrystalline anisotropy constant
([K.sub.u]) of ~[10.sup.6] erg [cm.sup.-3], which is not sufficient for the realization of high magnetic data storage density of over 2 Tb [in.sup.-2], are transformed from FM to PM phase after ion irradiation.
In Fe-Si grain oriented strips, the first magnetocrystalline anisotropy constant
[K.sub.1] is high and positive (3.5x[10.sup.4] J/[m.sup.3]) and therefore <100> is an easy direction, since the magnetocrystalline anisotropy energy is equal to zero.
where [M.sub.s] is the saturated magnetization, [t.sub.m] the measurement time, [[tau].sub.o] the attempt time, K the magnetic anisotropy constant
, H the applied magnetic field, [H.sub.c] the anisotropy field, [k.sub.B] the Boltzmann's constant, T the temperature and [Florin]([V.sub.b](T,H)) is the volume distribution of the magnetic particles.
The object is a cube with magnetization, [M.sub.s], exchange stiffness parameter, A, and magnetocrystalline anisotropy constant
[K.sub.u] = 0.1 X 1/2 [[micro].sub.o][M.sup.2.sub.s], with the easy direction parallel to a principle axis of the cube.
where [??] is a unit vector along the anisotropy axis, [K.sub.j] is the magnetic anisotropy constant
, and [??] is the magnetization of the bilayer of magnitude [M.sub.sj].
where [[sigma].sub.w] = [(2[k.sub.B][T.sub.C][absolute value of [K.sub.1]]/a).sup.1/2] is the domain wall energy, [k.sub.B] is Boltzmann constant, [T.sub.c] is Curie temperature, [K.sub.1] is magnetocrystalline anisotropy constant
, a is the lattice constant, and Ms is the saturation magnetization.
where [K.sub.eff] is the effective anisotropy constant
, [[mu].sub.0] is the magnetic permeability, and [M.sub.s] is the saturation magnetization.
In these materials the soft magnetic phase has higher inherent magnetization, and the hard magnetic phase has a higher anisotropy constant
and higher remanence; therefore, higher energy product will be achieved in comparison with single phase material because of exchange coupling between the magnetically soft and hard phases.
Magat, "Determination of the anisotropy constant
and saturation magnetization and magnetic properties of an iron-platinum alloy," Physics of Metals and Metallography, vol.
In the same paper was received experimental linear dependence of the effective anisotropy constant
of stress which is in good agreement with the results obtained by us (see (19)).