Huge magnetostriction in Tb3Fe5O12, Dy3Fe5O12, Ho3Fe5O12, Er3Fe5O12 garnets

Giant magnetostriction was observed in some ferromagnetic garnets: TbIG, DyIG, HoIG at low temperature. The λ111 magnetostrictive coefficients (deduced from the distortion of the lattice from cubic symmetry Ia3d at 300 K toward rhombohedral symmetry R3c at low temperature) reach respectively, +2400×10-6, -875×100-6 and -450×10-6 at 4.2 K. Magnetostriction and canted magnetic structure appear simultaneously and progressively at low temperature. The contribution to magnetostriction of the various anisotropic parameters (RE-iron exchange, crystal field acting on RE, spin-orbit coupling) are analysed.