1. Spintronics: Fundamentals and applications
2. The anisotropy axis is intrinsic and determined by the growth conditions and crystallography of the grain, whereas the EA is determined from all contributing energy terms (anisotropy, shape, demagnetization and mutual interactions when they occur between grains) except Zeeman, since it is the probe. The total energy minimum is achieved when the magnetization is along the resulting EA orientation.
3. All energies are taken per unit volume of the particle.
4. Anisotropy energy can be considered a contribution to energy given by the term Ksin2θ, where θ is the angle, the magnetization makes with the anisotropy axis. If K>0 the energy minimum (=0) occurs when θ=0, that is alignment with the anisotropy axis (easy axis case). If K<0, the energy minimum (-|K|) is obtained when θ=π/2 favoring an orientation perpendicular to the axis and hence in a plane perpendicular to it (easy plane case).
5. Physics of Ferromagnetism;Chikazumi,1997