Herein, the crystal structure and the magnetic and electrical properties of two Ga‐rich, off‐stoichiometric full Heusler‐type compositions ${\text{Ga}}_{2-x}{\text{Mn}}_{1+x}\text{Co}$ with x = 0.2 and 0.4 are investigated. The innate site disorder in the crystal structure is clarified using synchrotron X‐ray diffraction (XRD) studies. Experimentally, it is observed that a control over magnetic ordering temperature ( $T_{\mathrm{C}}$) and total magnetic moment can be achieved by tuning the Ga:Mn ratio in these alloys. Consequently, for the resultant compositions, ${\text{Ga}}_{1.8}{\text{Mn}}_{1.2}\text{Co}$ and ${\text{Ga}}_{1.6}{\text{Mn}}_{1.4}\text{Co}$, Curie temperatures of ≈245 and 375 K, respectively, are obtained, lying in the vicinity of room temperature. The atomic site disorder arising out of excess Mn leads to spin fluctuation scattering which is reflected in its magnetic and transport properties. Temperature dependence of resistivity shows an anomalous occurrence of a maximum, reflecting a change in the sign of the temperature coefficient of resistance, coincidental with $T_{\mathrm{C}}$. Furthermore, the magnetization results indicate an itinerant‐type ferromagnetic ground state over the Heisenberg‐type state, with the moment values as low as 0.35 ${\mu }_{\mathrm{B}}$.

中文翻译：

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富含Ga的Ga-Mn-Co完全Heusler合金中的巡回磁性

在这里，两种富含Ga的，化学计量失配的完整Heusler型成分的晶体结构以及磁和电性能 ${\text{嘎}}_{\mathrm{2个}-X}{\text{锰}}_{\mathrm{1个}+X}\text{有限公司}$与X  = 0.2和0.4进行了研究。使用同步加速器X射线衍射（XRD）研究可以澄清晶体结构中的先天位错。从实验上观察到，对磁序温度的控制（${Ť}_{\mathrm{C}}$）和总磁矩可以通过调整这些合金中的Ga：Mn比来实现。因此，对于所得的组合物，${\text{嘎}}_{1.8}{\text{锰}}_{1.2}\text{有限公司}$ 和 ${\text{嘎}}_{1.6}{\text{锰}}_{1.4}\text{有限公司}$在室温附近，居里温度分别约为245和375K。由过量Mn引起的原子位错会导致自旋涨落散射，这在其磁性和传输特性中得到了反映。电阻率的温度依赖性显示出现最大值的异常，反映了电阻温度系数的符号变化，与${Ť}_{\mathrm{C}}$。此外，磁化结果表明，在Heisenberg型态上有一个迭代型铁磁性基态，其矩值低至0.35${\mu }_{\mathrm{乙}}$。