We have studied the effects of hydrogenation on structure and magnetic properties of Fe (3.0 nm)/La (tnm) multilayers at the range of La layer thickness (t) from 0.3 to 4.2 nm. The effects of hydrogenation are the following. (a) All multilayers become a well-defined layered structure. (b) The bilayer thickness (Λ) becomes larger by a lattice expansion of only La layer. (c) The saturation magnetization (Ms)Fe of the multilayers becomes larger. The increment of (Ms)Fe is caused by the disproportionation of the Fe-La mixing layer to the pure Fe layer at the Fe/La interface. (d) The remanence ratio (Mr/Ms) and the saturation field (Hs) reflecting coupling state between the adjacent Fe layers change with increasing La layer thickness: the coupling state changes from a ferromagnetic (FM) state to a non-coupled (NC) state. This changing manner is the same, but the thickness range of spacer layer for FM coupling expands from 1.5 to 1.8 nm. This expansion of the thickness range is due to the change of interface structure and electronic structure caused by La-hydride formation.
Bibliographical noteFunding Information:
This work was partly supported by a Grant-in-Aid for Scientific Research (S) and Encouragement of Young Scientists (B) from the Japanese Ministry of Education, Culture, Sports, Science, and Technology. This work was also partially supported by ‘Priority Assistance od the Formation of Worldwide Renowned Centers of Research—The 21st Century COE program (Project: Center of Excellence for Advanced Structural and Functional Materials Design)’ from the Japanese Ministry of Education, Culture, Sports, Science, and Technology.
- Fe-La mixing layer
- Fe/La multilayer
- Ferromagnetic coupling
- Interlayer exchange coupling
- La-hydride layer