Abstract

Semiconductor–ferromagnet alloys in the CdAs₂–MnAs system were synthesized in evacuated ampules. Differential thermal analysis (DTA), X-ray powder diffraction analysis, differential scanning calorimetry, and scanning electron microscopy showed that this system is eutectic (of the acicular type), and the coordinates of the eutectic are (6 ± 0.5 mol % MnAs, T_melt = 614 ± 1°C). The liquidus lines constructed based on the thermal events of melting in DTA are 40–50°C higher than the lines constructed based on the thermal events of crystallization, which is due to the tendency of CdAs₂ toward glass transition. The synthesized alloys are ferromagnetic with T_C = 315 K, and the magnetization of them increases with increasing MnAs content. The alloys with nanoinclusions ≤40 nm of the ferromagnetic phase MnAs were produced by crystallization from melts at high cooling rates (≤100 deg/s). They have a higher Curie temperature of T_C = 353 K and a negative magnetoresistance of ΔR = 2% at 300 K in a saturation magnetic field of 4500 Oe, which is of practical interest for creating magnetic granular spintronic structures.

中文翻译：

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CdAs 2 -MnAs体系中铁磁性合金半导体-铁磁体的合成

摘要

在真空安瓿中合成了CdAs ₂ -MnAs系统中的半导体-铁磁体合金。差示热分析（DTA），X射线粉末衍射分析，差示扫描量热法和扫描电子显微镜显示该系统是共晶的（针状），共晶的坐标为（6±0.5 mol％MnAs，T_熔体＝ 614±1℃）。基于DTA熔融热事件构造的液相线比基于结晶热事件构造的液相线高40–50°C，这是由于CdAs ₂向玻璃化转变的趋势。合成的合金具有T _C的铁磁性= 315 K，并且它们的磁化强度随MnAs含量的增加而增加。纳米夹杂物≤40 nm的铁磁相MnAs是通过在高冷却速率（≤100 deg / s）下从熔体中结晶而制得的。它们在4500 Oe的饱和磁场中在300 K时具有较高的居里温度T _C = 353 K和负磁阻ΔR = 2％，这对于创建磁性粒状自旋电子结构具有实际意义。