Co_2MnZ(Z=Si,Ge)半金属Heusler合金原子反位无序的XRD研究

Study on the Antisite Disorder by XRD for the Half-metal of Co_2MnZ(Z=Si,Ge) Heusler Alloys

通过建立X2YZ三元亥斯勒(Heusler)合金原子无序度的XRD理论模型,计算并分析了Co2MnZ(Z=Si,Ge)合金中6类优先原子反位无序对(111)和(200)超晶格衍射峰相对强度的影响。对Co2MnSi亥斯勒合金的实验XRD结果分析表明,Co2MnSi合金中主要存在Co-Mn和Co-Mn-Co的原子反位无序。这一合金原子无序类型的XRD表征结果与中子衍射实验的结论相一致。

An X-ray diffraction （XRD） theoretical model for the characterization of antisite disorder in the ternary Heusler alloy system （X2YZ） is given. The effects of the antisite disorder defect on the intensity of superlatice reflection of （111） and （200） peaks relative to that of principal reflections are studied by the theoretical calculations and results analysis. The experimental XRD data of powdered of Co2MnSi single crystal was analyzed and the Co-Mn antisite disorder was found to be the main type of disorder exists in this specimen. XRD result is consistent with that concluded by Neutron-diffraction experiments for this sample.