The magnetization of magnetic materials is affected by two general types of anisotropy

The magnetization of magnetic materials is affected by two general types of anisotropy: bulk and surface. The most common sorts of the bulk anisotropy in nanomaterials are magnetocrystalline and shape anisotropy. The magnetocrystalline anisotropy is an intrinsic property of a material independent of its shape. In polycrystalline particles, containing some primary crystallites oriented in different directions, a tiny net magnetocrystalline anisotropy is expected due to averaging over all directions. The shape anisotropy, also known as the magnetostatic anisotropy, is the anisotropy of a magnetic material, which depends on its shape. Spheroidal magnetic nanoparticles, their shape will lead to a magnetization process, which is intrinsically uniform in all directions. On the other hand, non-spherical magnetic materials magnetize easier along the long axis than along a short one.