Inhaltszusammenfassung

We report on a comprehensive combined experimental and theoretical study of curie temperature trends in (ga,mn)as ferromagnetic semiconductors. broad agreement between theoretical expectations and measured data allows us to conclude that t-c in high-quality metallic samples increases linearly with the number of uncompensated local moments on mn-ga acceptors, with no sign of saturation. room temperature ferromagnetism is expected for a 10% concentration of these local moments. our magnetotrans...We report on a comprehensive combined experimental and theoretical study of curie temperature trends in (ga,mn)as ferromagnetic semiconductors. broad agreement between theoretical expectations and measured data allows us to conclude that t-c in high-quality metallic samples increases linearly with the number of uncompensated local moments on mn-ga acceptors, with no sign of saturation. room temperature ferromagnetism is expected for a 10% concentration of these local moments. our magnetotransport and magnetization data are consistent with the picture in which mn impurities incorporated during growth at interstitial mn-i positions act as double-donors and compensate neighboring mn-ga local moments because of strong near-neighbor mn-ga-mn-i antiferromagnetic coupling. these defects can be efficiently removed by post-growth annealing. our analysis suggests that there is no fundamental obstacle to substitutional mn-ga doping in high-quality materials beyond our current maximum level of 6.8%, although this achievement will require further advances in growth condition control. modest charge compensation does not limit the maximum curie temperature possible in ferromagnetic semiconductors based on (ga,mn)as.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
3.17 - Theoretische Chemie

DDC Sachgruppe:
Physik