Microscopic Magnetic Characterization of Quantum Criticality in LaCrGe3

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The fluctuations, associated with quantum-critical points (QCP), i.e., second-order phase transitions at zero temperature, have been considered crucial for the stabilization of intriguing phenomena, such as superconductivity or non-Fermi liquid behavior. Expanding on earlier work which strongly suggest that a short-range magnetically ordered cluster phase

 Microscopic Magnetic Characterization of Quantum Criticality in LaCrGe3
Temperature-pressure (T-p) phase diagram of LaCrGe3 from Ref. [1]. The red circles show ferromagnetic phase transition temperatures determined by the NMR measurements under 7.4 T.

emerges as the ferromagnetic transition is suppressed towards zero temperature LaCrGe3, 139La nuclear magnetic resonance (NMR) measurements under pressure up to 2.64 GPa were performed. The NMR results are consistent with the recently proposed short-range ferromagnetic order. Furthermore, it is shown that the three-dimensional ferromagnetic fluctuations in the paramagnetic state persist and are robust even at pressures close to the putative QCP. LaCrGe3 might stand as a peculiar system having a new route to avoid a ferromagnetic quantum critical point by not only changing the order of the phase transition but also through the appearance of the high-pressure magnetic phase mainly dominated by ferromagnetic interactions. To understand the nature of the avoidance of ferromagnetic quantum criticality in LaCrGe3, further detailed studies under lower magnetic fields as well as higher pressures will be required.

“Magnetic properties of the itinerant ferromagnet LaCrGe3 under pressure studied by 139La NMR” K. Rana, H. Kotegawa, R. R. Ullah, E. Gati, S. L. Bud’ko, P. C. Canfield, H. Tou, V. Taufour, and Y. Furukawa, Phys. Rev. B 103 174426 (2021) (Editors’ suggestion) DOI: 10.1103/PhysRevB.103.174426