Quasi-local critical nature of cooperative paramagnetic fluctuations in CaRuO$_{3}$ metal

TL;DR

This study uncovers quasi-local critical cooperative paramagnetic fluctuations in CaRuO₃ below 22 K, linking them to its non-Fermi liquid behavior through detailed magnetic and neutron scattering analyses.

Contribution

It provides new evidence of quantum critical cooperative paramagnetic fluctuations in CaRuO₃ and their role in its non-Fermi liquid state, using comprehensive experimental techniques.

Findings

Observation of cooperative paramagnetic fluctuations below 22 K.

Evidence of quasi-local critical behavior in spin fluctuations.

Link between quantum critical fluctuations and non-Fermi liquid behavior.

Abstract

We report new observation of cooperative paramagnetic fluctuations of Ru$^{4+}$ spins that coexist with the non-Fermi liquid state in CaRuO$_{3}$ perovskite below T $\simeq$ 22 K. Detailed electrical, magnetic and neutron scattering measurements reveal that the Ru$^{4+}$ ions reside in magnetic field independent random domains with dynamic properties that are reminiscent of the cooperative paramagnetic fluctuations. The linear ($E/T$) scaling of the dynamic susceptibilities and divergence of the mean relaxation time as $T$$\rightarrow$~0 K suggest quasi-local critical nature of the spin fluctuations. We argue that the non-Fermi liquid behavior arises due to the quantum critical nature of the cooperative paramagnetic fluctuations in CaRuO$_{3}$