Gd-doped GaN: A very dilute ferromagnetic semiconductor with a Curie temperature above 300 K

摘要: We present a systematic study of growth, structural, and magnetic characterization $\mathrm{GaN}:\mathrm{Gd}$ layers grown directly on 6H-SiC(0001) substrates by reactive molecular-beam epitaxy with Gd concentration ranging from $7\ifmmode\times\else\texttimes\fi{}{10}^{15}$ to $2\ifmmode\times\else\texttimes\fi{}{10}^{19}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$. The structural properties these are found be identical those undoped GaN layers. However, the reveals an unprecedented effect. average value moment per atom is as high $4000\phantom{\rule{0.3em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}$ compared its atomic $8\phantom{\rule{0.3em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}$. Such colossal can explained in terms long range spin polarization matrix atoms which reflected circular magnetophotoluminescence measurements. Moreover, material system exhibit ferromagnetism well above room temperature entire under investigation. propose phenomenological model understand macroscopic behavior system. Our close connection between observed Gd.