MnScN(001)/MgO(001) films grown by molecular beam epitaxy: a possible dilute magnetic semiconductor.

Considerable interest has been of late in finding a room temperature dilute magnetic semiconductor. Recently, theoretical calculations had predicted Curie temperature to be above 400 K for the films with 3{\%} Mn concentration into the Mn$_{x}$Sc$_{(1-x)}$N system\footnote{ Aditi Herwadkar and Walter R. L. Lambrecht, Phys. Rev. B \textbf{72}, 235207 (2005).\par \par }. In this study, Mn$_{x}$Sc$_{(1-x)}$N films (with x = 3-5{\%}) were grown on ScN(001)/MgO(001) substrates by radio frequency plasma assisted molecular beam epitaxy. The buffer layer of ScN(001) was grown on top of MgO(001) at T$_{S}\sim $ 800 $^{^{\circ}}$C and with a thickness of $\sim $ 50 nm. The MnScN film was grown at T$_{s}\sim $ 520 $^{^{\circ}}$C and with a thickness of $\sim $ 290 nm. Post-growth x-ray diffraction measurements show that Mn$_{x}$Sc$_{(1-x)}$N alloys follow the Vegard's law. The hysteresis magnetic data measured with the superconducting quantum interference device show possible ferromagnetic behavior for the Mn$_{0.03}$Sc$_{0.97}$N films with a Curie temperature of $\sim $50 K, but additional data is needed to establish the conclusiveness of the results. Work supported by NSF.