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Yamamoto, Shingo*; Fujii, Takuto*; Luther, S.*; Yasuoka, Hiroshi*; Sakai, Hironori; Brtl, F.*; Ranjith, K. M.*; Rosner, H.*; Wosnitza, J.*; Strydom, A. M.*; et al.
Physical Review B, 106(11), p.115125_1 - 115125_5, 2022/09
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)We have studied the microscopic magnetic properties, the nature of the 130 K phase transition, and the ground state in the recently synthesized compound CeRhGa by use of Ga nuclear quadrupole resonance (NQR). The NQR spectra clearly show an unusual phase transition at K, yielding a splitting of the high-temperature single NQR line into two well-resolved NQR lines, providing evidence for two crystallographically inequivalent Ga sites. The NQR frequencies are in good agreement with fully relativistic calculations of the band structure. Our NQR results indicate the absence of magnetic or charge order down to 0.3 K. The temperature dependence of the spin-lattice relaxation rate shows three distinct regimes, with onset temperatures at and 2 K. The temperature-independent , observed between and 2 K, crosses over to a Korringa process, , below 2 K, which evidences a rare two-ion Kondo scenario: The system evolves into a dense Kondo coherent state below 2.0 and 0.8 K probed by the two different Ga sites.
Yasuoka, Hiroshi; Kubo, Tetsuro*; Kishimoto, Yasuki*; Kasinathan, D.*; Schmidt, M.*; Yan, B.*; Zhang, Y.*; To, Hideki*; Felser, C.*; Mackenzie, A. P.*; et al.
Physical Review Letters, 118(23), p.236403_1 - 236403_6, 2017/07
Times Cited Count:29 Percentile:82.8(Physics, Multidisciplinary)The Ta quadrupole resonance (NQR) technique has been utilized to investigate the microscopic magnetic properties of the Weyl semi-metal TaP. We found three zero-field NQR signals associated with the transition between the quadrupole split levels for Ta with =7/2 nuclear spin. A quadrupole coupling constant, = 19.250 MHz, and an asymmetric parameter of the electric field gradient, = 0.423 were extracted, in good agreement with the theoretical calculations. In order to examine the magnetic excitations, the temperature dependence of the spin lattice relaxation rate (1/) has been measured for the -line ( transition). We found that there exist two regimes with quite different relaxation processes. Above *K, a pronounced ( behavior was found which is attributed to the magnetic excitations at the Weyl nodes with temperature dependent orbital hyperfine coupling. Below *, the relaxation is mainly governed by Korringa process with (1/) = constant, while we have to include a type dependence in order to reproduce our experimental data. We show that Ta-NQR is a novel probe for the bulk Weyl fermions and their excitations.
Yasuoka, Hiroshi; Motoya, Kiyoichiro*; Majumder, M.*; Witt, S.*; Kerllner, C.*; Baenitz, M.*
Journal of the Physical Society of Japan, 85(7), p.073701_1 - 073701_4, 2016/07
Times Cited Count:3 Percentile:27.79(Physics, Multidisciplinary)