Adjustable magnetic interactions: the use of hydrogen as a tuning agent

• Published in: Journal of alloys and compounds 2003-08, Vol.356-357, p.160-168
• Main Authors: Hjörvarsson, B., Chacon, C., Zabel, H., Leiner, V.
• Format: Article
• Language: English
• Subjects: Exchange coupling; Hydrogen; Multilayers; Rare earth metals; Superlattices; Thin films; Transition metals
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(03)00168-3

The use of hydrogen to modify the electronic structure in magnetic thin films and heterostructures has opened new routes to tailor magnetic interactions in materials. The presence of hydrogen modifies the electronic structure of the host. Hydrogen can therefore be used to control the strength and character of magnetic interactions. This effect can be used to change the coupling strength in thin films, as well as selectively altering one of the constituents in artificial heterostructures. For example, the switching from antiferromagnetic to ferromagnetic order, and vice versa, has been demonstrated for exchange coupled magnetic superlattices. As the sign of the interlayer exchange coupling J′ can be switched by the insertion of hydrogen, J′ arbitrarily close to zero must be accessible. When J′=0, the exchange interaction between adjacent magnetic layers is completely suppressed. The heterostructure can then be taken to consist of a collection of quasi two-dimensional magnetic sheets, when the ferromagnetic layers are very thin. Consequently, the introduction of hydrogen can be viewed as a route to tune the dimensionality of these structures.