The influence of Co on the crystal structure and magnetic properties of the Ga_2−xMnNiCo_x (x = 0,0.3,0.5,0.7) are investigated in this study. It has been found that the doping of Co does not change the cubic Heusler structure of the parent compound Ga₂MnNi. The introduction of a small amount of Co reduces the p-d covalent hybridization effect and decreases the degree of atomic ordering, resulting in an abnormal increase in the lattice parameter when x = 0.3 (from 5.8387 ± 0.0020 Å to 5.8665 ± 0.0012 Å). The atomic size effect plays the main role when x > 0.3, leading to the decrease of lattice parameter. Due to the influence of the lattice parameter and the atomic site occupation on the magnetic interaction, the Curie temperature (T_C) and the saturation magnetization are found to decrease at first and then increase with the chemical substitution of Co for Ga. A reentrant spin glass (RSG) below T_f = 65.8 K is confirmed in Ga_1.5MnNiCo_0.5 alloy due to the competition of ferromagnetic and antiferromagnetic interactions.

本研究研究了 Co 对 Ga _2-x MnNiCo _x (x = 0,0.3,0.5,0.7)晶体结构和磁性能的影响。已经发现，Co的掺杂不会改变母体化合物Ga ₂ MnNi的立方赫斯勒结构。少量 Co 的引入降低了pd共价杂交效应并降低了原子有序度，导致 x = 0.3 时晶格参数异常增加（从 5.8387 ± 0.0020 Å 到 5.8665 ± 0.0012 Å）。当 x > 0.3 时，原子尺寸效应起主要作用，导致晶格参数降低。由于晶格参数和原子位置对磁相互作用的影响，居里温度（发现 T _C ) 和饱和磁化强度随着 Co 对 Ga 的化学取代首先降低然后增加。由于竞争， 在 Ga _1.5 MnNiCo _0.5合金中证实了低于T _f = 65.8 K 的重入自旋玻璃 (RSG)铁磁和反铁磁相互作用。