Existence and origin of compensation layer thickness in Tb ₂₀Co₈₀/Pd multilayered films

Magnetic properties of [Tb₂₀Co₈₀/Pd(0.8 nm)] ₂₀ multilayered films with a TbCo layer of thickness 0.2-8.0 nm were studied using spectroscopic techniques of soft x-ray absorption (XAS) and magnetic circular dichroism (MCD) at the Co L_2,3 and Tb M _4,5 edges. The compensation layer thickness of TbCo, where magnetization becomes zero, was observed to be 5-6 nm. XAS and MCD analyses using the sum rule revealed that the existence of the compensation layer thickness was primarily because the projected Tb 4f magnetic moment was enhanced with the increase in the layer thickness, while the Co 3d moment was independent of the layer thickness. Below the compensation layer thickness, Co sublattice magnetization was dominant.