Evolution of ferrimagnetism against Griffiths singularity in calcium ruthenate.
Pooja KesarwaniSachindra Nath SarangiDebakanta SamalChanchal SowPublished in: Journal of physics. Condensed matter : an Institute of Physics journal (2024)
The magnetism in the correlated metal CaRuO 3 is 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-xCr x O 3 . We find that Cr doping reduces the orthorhombicity in CaRuO 3 . Surprisingly, a tiny ( x = 0.01) amount of Cr-doping drives the magnetic ground state from 'paramagnetic-like' to ferrimagnetic. Slightly higher Cr-doping ( x = 0.05) results formation of magnetic clusters which gives rise to Griffiths singularity and power law divergence in magnetic susceptibility. The magnetism in CaRu1-xCr x O 3 is 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 x ⩾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-xCr x O 3 .