Enhanced Sm spin projection in GdxSm1−xN

The rare-earth nitrides form a series of structurally simple intrinsic ferromagnetic semiconductors, a rare class of both fundamental interest and application potential. Within the series there is a wide range of magnetic properties relating to the spin/orbit contributions to the ferromagnetic ground states. We report an x-ray magnetic circular dichroism investigation of the spin/orbit magnetic dipole alignments of Sm and Gd ions in epitaxial ${\mathrm{Gd}}_{x}{\mathrm{Sm}}_{1\ensuremath{-}x}\mathrm{N}$ films. The Sm spin-alignment expectation value $\ensuremath{\langle}{S}_{z}\ensuremath{\rangle}$ is seen to be strengthened by the Gd/Sm exchange interaction, providing guidance that the composition for an angular momentum compensation point, where the volume-averaged total angular momentum of a film is zero, lies near $x=0.24$.