Abstract
β-Mn-type family alloys Mn3TX (T=Co, Rh, and Ir; X=Si and Ge) have a three-dimensional antiferromagnetic (AF) corner-shared triangular network, i.e., the hyperkagome lattice. The antiferromagnet Mn3RhSi shows magnetic short-range order over a wide temperature range of approximately 500 K above the Néel temperature TN of 190 K. In this family of compounds, as the lattice parameter decreases, the long-range magnetic ordering temperature decreases. Mn3CoSi has the smallest lattice parameter and the lowest TN in the family. The quantum critical point (QCP) from AF to the quantum paramagnetic state is expected near a cubic lattice parameter of 6.15 Å. Although the Néel temperature of Mn3CoSi is only 140 K, the emergence of the quantum critical behavior in Mn3CoSi is discussed. We study how the magnetic short-range order appears in Mn3CoSi by using neutron scattering, μSR, and bulk characterization such as specific heat capacity. According to the results, the neutron scattering intensity of the magnetic short-range order in Mn3CoSi does not change much at low temperatures from that of Mn3RhSi, although the μSR short-range order temperature of Mn3CoSi is largely suppressed to 240 K from that of Mn3RhSi. Correspondingly, the volume fraction of the magnetic short-range order regions, as shown by the initial asymmetry drop ratio of μSR above TN, also becomes small. Instead, the electronic-specific heat coefficient γ of Mn3CoSi is the largest in this Mn3TSi system, possibly due to the low-energy spin fluctuation near the quantum critical point.
Original language | English |
---|---|
Article number | 013144 |
Journal | Physical Review Research |
Volume | 6 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2024 |
Funding
This work at J-PARC was performed at NOVA(BL21, 2021B0074, 2020B0415), SENJU(BL18, 2022A0263), POLANO(BL23, 2022A0202), and 4SEASONS (BL01, 2021C0001). The neutron scattering experiment at WAND of ORNL was partly supported by the U.S.-Japan Cooperative Program on Neutron Scattering under the proposals of 11391 and 13776. A portion of this research was performed using resources at the ORNL HFIR and was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. This work at FONDER was performed by the JRR-3 general user program managed by the Institute for Solid State Physics, the University of Tokyo, under the proposal of 22812. This work at HRPD was performed by the JRR-3 general user program managed by Japan Atomic Energy Agency. The muon spin spectroscopy was performed at ARGUS of ISIS under the proposals of RB1870002 and RB2070006 and at M20 of TRIUMF under the proposal of M2201. We would like to thank Prof. T. Nakajima, Drs. S. Onoda, M. Nakamura and K. Kamazawa for valuable discussions and their help. This work was supported by Grants-in-Aid for Scientific Research (C) (No. 22K04678) from the Japan Society for the Promotion of Science. The works at National Cheng Kung University were supported by the Project NSTC 112-2112-M-006-031. The work at the University of Warwick was funded by EPSRC, UK, through Grants No. EP/N032128/1 and No. EP/T005963/1. The crystal check was performed using an X-ray Laue camera at the MLF first experiment preparation room and a magnetic properties measurement system at the CROSS user laboratory II.