GaMnAs films are prepared by low-temperature molecular beam epitaxy.Based on the experimental results,the influence of growth and annealing conditions on the physical properties and defect configurations is discussed....GaMnAs films are prepared by low-temperature molecular beam epitaxy.Based on the experimental results,the influence of growth and annealing conditions on the physical properties and defect configurations is discussed.In particular,the major compensating defects,such as As antisite(A_(sGa))and Mn interstitials(Mn_(I)),are studied in detail.Thereby,the relationship between structure and magnetic properties is given.It is indicated that a higher annealing temperature can remove MnI out of the GaMnAs lattices so as to raise the Curie temperature TC.Meticulous optimization of growth techniques(T_(S)=230℃,A_(s2):Ga=5:1 and Ta=250℃)leads to reproducible physical properties and ferromagnetic transition temperatures well above 148 K.展开更多
A model for analyzing point defects in com-pound crystals was improved. Based on this modified model, a method for measuring Mn content in GaMnAs was estab-lished. A technique for eliminating the zero-drift-error was ...A model for analyzing point defects in com-pound crystals was improved. Based on this modified model, a method for measuring Mn content in GaMnAs was estab-lished. A technique for eliminating the zero-drift-error was also established in the experiments of X-ray diffraction. With these methods, the Mn content in GaMnAs single crystals fabricated by the ion-beam epitaxy system was analyzed.展开更多
基金by the National Natural Science Foundation of China under Grant No 61006010Shandong-Provincial Higher Educational Science and Technology Program under Grant No J11LA58.
文摘GaMnAs films are prepared by low-temperature molecular beam epitaxy.Based on the experimental results,the influence of growth and annealing conditions on the physical properties and defect configurations is discussed.In particular,the major compensating defects,such as As antisite(A_(sGa))and Mn interstitials(Mn_(I)),are studied in detail.Thereby,the relationship between structure and magnetic properties is given.It is indicated that a higher annealing temperature can remove MnI out of the GaMnAs lattices so as to raise the Curie temperature TC.Meticulous optimization of growth techniques(T_(S)=230℃,A_(s2):Ga=5:1 and Ta=250℃)leads to reproducible physical properties and ferromagnetic transition temperatures well above 148 K.
基金This work was jointly supported by the Ministry of Chinese National Science and Technology (Grant No. PAN95-YU-34) Special Funds for Major State Basic Research Projects (Grant Nos. G20000683 and G20000365) the National Natural Science Foundation of
文摘A model for analyzing point defects in com-pound crystals was improved. Based on this modified model, a method for measuring Mn content in GaMnAs was estab-lished. A technique for eliminating the zero-drift-error was also established in the experiments of X-ray diffraction. With these methods, the Mn content in GaMnAs single crystals fabricated by the ion-beam epitaxy system was analyzed.
