Fermi-Surface Topology and Helical Antiferromagnetism in Heavy Lanthanide Metals.
Journal - Physical review letters
Detailed angle-resolved photoemission studies of Tb and Dy metal in the paramagnetic phase provide direct experimental proof of the presence of nesting features in the Fermi surfaces (FS) of these heavy lanthanide (Ln) metals. The observations clearly support the hypothesis that nesting of the FS in the paramagnetic phase is responsible for the development of helical antiferromagnetic ordering in heavy Ln metals. They also show that magnetic exchange splitting of the electronic states is responsible for the disappearance of FS nesting in the ferromagnetic phases.
Temperature-induced reversal of magnetic interlayer exchange coupling.
Journal - Physical review letters (United States )
For epitaxial trilayers of the magnetic rare-earth metals Gd and Tb, exchange coupled through a nonmagnetic Y spacer layer, element-specific hysteresis loops were recorded by the x-ray magneto-optical Kerr effect at the rare-earth M5 thresholds. This allowed us to quantitatively determine the strength of interlayer exchange coupling (IEC). In addition to the expected oscillatory behavior as a function of spacer-layer thickness dY, a temperature-induced sign reversal of IEC was observed for constant dY, arising from magnetization-dependent electron reflectivities at the magnetic interfaces.