TY - JOUR
T1 - Local spin dynamics in the geometrically frustrated Mo pyrochlore antiferromagnet Lu2Mo2 O5-y N2
AU - Dey, S. K.
AU - Ishida, K.
AU - Okabe, H.
AU - Hiraishi, M.
AU - Koda, A.
AU - Honda, T.
AU - Yamaura, J.
AU - Kageyama, H.
AU - Kadono, R.
N1 - Funding Information:
We thank helpful discussions with H. Kawamura and M. J. P. Gingras. Thanks are also to the MLF staff for their technical support for the muon experiment, which was conducted under the support of Inter-University-Research Programs (IURP, Proposals No. 2020B0388, 2020MI21, and 2021MI21) by Institute of Materials Structure Science (IMSS), KEK. XANES experiments were conducted under the support of IURP (Proposals No. 2021V004) by IMSS, KEK. The neutron scattering experiment received approval from the Neutron Scattering Program Advisory Committee of IMSS, KEK (Proposal No. 2019S06). S.K.D. also acknowledges support from Y. Nagatani, and K. Shimomura. Thanks are also to H. Lee for helping DFT calculations. This work was partly supported by the JSPS KAKENHI Grant No. 16H06439 and by the Elements Strategy Initiative to Form Core Research Centers, from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT) under Grant No. JPMXP0112101001.
Publisher Copyright:
© 2023 American Physical Society.
PY - 2023/1/1
Y1 - 2023/1/1
N2 - The magnetic ground state of oxynitride pyrochlore Lu2Mo2O5-yN2, a candidate compound for the quantum spin liquid (S=1/2, Mo5+), was studied by muon spin rotation/relaxation experiment. In contrast to Lu2Mo2O7 (S=1, Mo4+) which exhibits the spin-glass behavior with a freezing temperature Tg≃16K, no such spin freezing or long-range magnetic order was observed down to 0.3 K. Moreover, two separate magnetic domains were detected below ∼13K, which were characterized by differences in spin dynamics. The first is the "sporadic"spin fluctuation seen in frustrated antiferromagnets, where the amplitude of the hyperfine fields suggests that the excitation comprises a local cluster of unpaired spins. The other is rapid paramagnetic fluctuation, which is only weakly suppressed at low temperatures. In place of the paramagnetic fluctuation, the volume fraction for the sporadic fluctuation steadily increases with decreasing temperature, indicating the formation of an excitation gap with a broad distribution of the gap energy involving a null gap.
AB - The magnetic ground state of oxynitride pyrochlore Lu2Mo2O5-yN2, a candidate compound for the quantum spin liquid (S=1/2, Mo5+), was studied by muon spin rotation/relaxation experiment. In contrast to Lu2Mo2O7 (S=1, Mo4+) which exhibits the spin-glass behavior with a freezing temperature Tg≃16K, no such spin freezing or long-range magnetic order was observed down to 0.3 K. Moreover, two separate magnetic domains were detected below ∼13K, which were characterized by differences in spin dynamics. The first is the "sporadic"spin fluctuation seen in frustrated antiferromagnets, where the amplitude of the hyperfine fields suggests that the excitation comprises a local cluster of unpaired spins. The other is rapid paramagnetic fluctuation, which is only weakly suppressed at low temperatures. In place of the paramagnetic fluctuation, the volume fraction for the sporadic fluctuation steadily increases with decreasing temperature, indicating the formation of an excitation gap with a broad distribution of the gap energy involving a null gap.
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U2 - 10.1103/PhysRevB.107.024407
DO - 10.1103/PhysRevB.107.024407
M3 - Article
AN - SCOPUS:85146329147
SN - 2469-9950
VL - 107
JO - Physical Review B
JF - Physical Review B
IS - 2
M1 - 024407
ER -