Ferromagnic Transitition Temperature of Diluted Magnetic III-V Based Semiconductor

III-V 화합물 자성 반도체의 강자성체 천이온도에 관한 연구

Ferromagnetism in manganese compound semiconductors open prospects for tailoring magnetic and spin-related phenomena in semiconductors with a precision specific to III-V compounds. Also it addresses a question about the origin of the magnetic interactions that lead to a Curie temperature(Tc) as high as 110 K for a manganese concentration of just 5%. Zener's model of ferromagnetism, originally suggested for transition metals in 1950, can explain Tc of $Ga_{1-x}Mn_x$ As and that of its IT-VI counterpart $Zn_{1-x}Mn_x$ Te and is used to predict materials with Tc exceeding room temperature, an important step toward semiconductor electronics that use both charge and spin. In this article, we present not only the experimental result but calculated Curie temperature by RKKY interaction. The problem in making III-V semiconductor has been the low solubility of magnetic elements, such as manganese, in the compound, since the magnetic effects are roughly proportional to the concentration of the magnetic ions. Low solubility of magnetic elements was overcome by low-temperature nonequilibrium MBE{molecular beam epitaxy) growth, and ferromagnetic (Ga,Mn)As was realized. Magnetotransport measurements revealed that the magnetic transition temperature can be as high as 110 K for a small manganese concentration.