Ferromagnetic phenomena

Magnetic order in a crystal can influence the lattice parameters and the elastic moduli. These effects reflect the volume or strain dependence of bandwidth, exchange energy, magnetic dipole energy or crystal-field interaction. Some effects, like linear magnetostriction, are small, λ_s ≈ 10⁻⁵. Others like the  ΔE effect, the change of Young’s modulus associated with domain alignment, can be as large as 90%. Even very small magnetoelastic effects may be critical when optimizing the properties of soft magnets, because of the sensitivity of coercivity to stress-induced anisotropy. Ferromagnetism also influences the thermal, electrical and optical properties of solids. These intrinsic effects in ferromagnets are discussed in the following paragraphs.