Kesarwani Pooja, Nath Sarangi Sachindra, Samal D, Sow Chanchal
Department of Physics, Indian Institute of Technology, Kanpur 208016, India.
Institute of Physics, Bhubaneswar 751005, India.
J Phys Condens Matter. 2024 Apr 5;36(26). doi: 10.1088/1361-648X/ad3707.
The magnetism in the correlated metal CaRuOis enigmatic as it is poised near a triple point among the ferromagnetic, antiferromagnetic, and paramagnetic ground states. Here we report a detailed work on structural, spectroscopic, magnetic, and transport properties in CaRu1-xCrO. We find that Cr doping reduces the orthorhombicity in CaRuO. Surprisingly, a tiny (= 0.01) amount of Cr-doping drives the magnetic ground state from 'paramagnetic-like' to ferrimagnetic. Slightly higher Cr-doping (= 0.05) results formation of magnetic clusters which gives rise to Griffiths singularity and power law divergence in magnetic susceptibility. The magnetism in CaRu1-xCrOis explained in terms of 'seven atom' ferrimagnetic clusters. Electrical transport shows a gradual evolution of a non-metallic state upon Cr-doping. In particular, for⩾0.1, the temperature-dependent resistivity follows Mott-VRH conduction. The XPS study also supports significant role of disorder and electron correlation which effectively reduces the itinerant character of electrons. Finally, a new T-x phase diagram is constructed depicting the evolution of electronic and magnetic state in CaRu1-xCrO.
关联金属CaRuO中的磁性很神秘，因为它处于铁磁、反铁磁和顺磁基态的三相点附近。在此，我们报告了一项关于CaRu1-xCrO的结构、光谱、磁性和输运性质的详细研究。我们发现Cr掺杂降低了CaRuO中的正交性。令人惊讶的是，微量（= 0.01）的Cr掺杂将磁基态从“类顺磁”转变为亚铁磁。稍高的Cr掺杂量（= 0.05）导致磁团簇的形成，这在磁化率中产生了格里菲斯奇点和幂律发散。CaRu1-xCrO中的磁性是根据“七原子”亚铁磁团簇来解释的。电输运显示出Cr掺杂后非金属态的逐渐演变。特别是，对于⩾0.1，与温度相关的电阻率遵循莫特变程跳跃传导。XPS研究也支持无序和电子关联的重要作用，这有效地降低了电子的巡游特性。最后，构建了一个新的T-x相图，描绘了CaRu1-xCrO中电子和磁态的演变。
