Complex sentence: The width of the domain wall varies due to the two opposing energies that create it: the Magnetocrystalline anisotropy energy and the exchange energy (Jex), both of which want to be as low as possible so as to be in a more favourable energtetic state.
Split into simpler sentences: The width of the domain wall varies due to the two opposing energies that create it: the Magnetocrystalline anisotropy energy and the exchange energy (Jex). Both of which want to be as low as possible so as to be in a more favourable energtetic state.