Tuning Magnetic Phases Via Hydrostatic Pressure in Kondo Lattice Antiferromagnet CeNiAsO

My research focuses on quantum materials that exhibit complex phenomena such as unconventional superconductivity, charge ordering, and distinct magnetic phases. Particularly, my work investigates how non-thermal parameters modify magnetic phases in quantum materials with tunable properties. The system I will present here is CeNiAsO, a Kondo lattice metal structurally analogous to iron-pnictides. In CeNiAsO, a quantum critical point (QCP) is proposed to be induced by applying pressure at critical pressure p_c ~ 6.5 kbar. At the QCP, the material exhibits non-Fermi-liquid behaviour with a divergent effective carrier mass [1]. The system exhibits two antiferromagnetic phases, an incommensurate spin density wave at T_N1 ~ 8.3 K, followed by a transition to a non-collinear commensurate state at T_N2 ~ 7.6 K [2]. My work aims to investigate how the two magnetic phases evolve as a function of applied pressure as they approach the putative magnetic QCP. Muon spin relaxation (μSR) experiments were used to probe the local magnetic properties by varying pressures and temperatures at the Paul Scherrer Institute. I analyzed the data with MuSRfit and Python software to extract relevant parameters, enabling characterization of pressure-driven magnetic phase evolution approaching the proposed QCP in CeNiAsO.

References:

1. Luo, Y., Pourovskii, L., Rowley, S. et al. Heavy-fermion quantum criticality and destruction of the Kondo effect in a nickel oxypnictide. Nature Mater 13, 777–781 (2014).

2. Wu, S., Phelan, W. A., Liu, L., Morey, J. R., Tutmaher, J. A., Neuefeind, J. C., Huq, A., Stone, M. B., Feygenson, M., Tam, D. W., Frandsen, B. A., Trump, B., Wan, C., Dunsiger, S. R., McQueen, T. M., Uemura, Y. J., & Broholm, C. L. Incommensurate magnetism near quantum criticality in CeNiAsO. Phys. Rev. Lett. 122, 197203 (2019).