Institute of Physics Bhubaneswar, Bhubaneswar 751005, India.
Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India.
J Phys Condens Matter. 2023 Jun 29;35(39). doi: 10.1088/1361-648X/ace0ac.
Realizing the itinerant type of magnetic exchange in Mn-based alloys is quite unusual because of the weak hybridization between Mn-moments and conduction electrons. However, in the current study, we found MnFeGe to exhibit weak itinerant type magnetic character possibly arising due to the hybridization between Mn, Fe atoms with Ge atoms. Here, we present a comprehensive structural and magnetic study on polycrystalline MnFeGe. Rietveld refinement of the XRD pattern confirms that Mn and Fe atoms randomly (atomic disorder) occupy theandsites in MnFeGe. From the magnetic measurements, Curie temperature and saturation moment values are found to be 162 K and 1.58μB/f.u.at 2 K, respectively. The relative low values of Curie temperature, saturation magnetic moment, and a large value of Rhodes-Wohlfarth ratio (∼3.4) indicate the weak itinerant ferromagnetic character of the system. The Takahashi spin fluctuation theory analysis further supports the weak itinerant ferromagnetism in MnFeGe. Besides, we also observed Griffiths phase (GP) like behavior above the Curie temperature, which is attributed to the presence of atomic disorder in the system. The presence of GP is further confirmed by the zero spontaneous magnetization. Our findings demonstrate that MnFeGe is one of the very few Mn-based systems with weak itinerant magnetic behavior.
在 Mn 基合金中实现巡游型磁交换是相当不寻常的，因为 Mn 磁矩和传导电子之间的杂化作用很弱。然而，在目前的研究中，我们发现 MnFeGe 表现出弱的巡游型磁特性，这可能是由于 Mn、Fe 原子与 Ge 原子之间的杂化所致。在这里，我们对多晶 MnFeGe 进行了全面的结构和磁性研究。XRD 图谱的Rietveld 精修证实，Mn 和 Fe 原子随机（原子无序）占据 MnFeGe 的andsites。从磁性测量结果来看，居里温度和饱和磁矩值分别在 2 K 时为 162 K 和 1.58μB/f.u.。居里温度、饱和磁矩相对较低，Rhodes-Wohlfarth 比（约 3.4）较大，表明该体系具有较弱的巡游铁磁性。Takahashi 自旋涨落理论分析进一步支持了 MnFeGe 中的弱巡游铁磁性。此外，我们还在居里温度以上观察到 Griffiths 相（GP）类似的行为，这归因于体系中存在原子无序。零自发磁化进一步证实了 GP 的存在。我们的研究结果表明，MnFeGe 是少数具有弱巡游磁性的 Mn 基体系之一。
