Spin dynamics in Na4-xIr3O8 (x=0.3 and 0.7) investigated by Na-23 NMR and mu SR
- Authors
- Yoon, Sungwon; Baek, S-H; Balodhi, Ashiwini; Lee, W-J; Choi, K-Y; Watanabe, I.; Lord, J. S.; Buechner, B.; Suh, B. J.; Singh, Yogesh
- Issue Date
- Dec-2015
- Publisher
- IOP PUBLISHING LTD
- Keywords
- hyperkagome; frustrated spin systems; insulator-metal transition
- Citation
- JOURNAL OF PHYSICS-CONDENSED MATTER, v.27, no.48
- Journal Title
- JOURNAL OF PHYSICS-CONDENSED MATTER
- Volume
- 27
- Number
- 48
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/8817
- DOI
- 10.1088/0953-8984/27/48/485603
- ISSN
- 0953-8984
1361-648X
- Abstract
- We report Na-23 nuclear magnetic resonance (NMR) and zero-field (ZF) and longitudinal-field (LF) muon spin relaxation (mu SR) measurements of the depleted hyperkagome compounds Na4-xIr3O8 (x = 0.3 and 0.7), which undergo an insulator-semimetal transition as a function of x. The Na-23 spin-lattice relaxation rates, T-1(-1), follow a T-2.5 power law behavior at accessible temperatures of T = 120-350 K. A substantial temperature dependence of T-1(-1) indicates the presence of gapped excitations at elevated temperatures through the transition to a semimetallic phase. ZF-mu SR results reveal that hole-doping leads to a melting of quasi-static order to a dynamically fluctuating state. The very slow muon depolarization rate which varies hardly with temperature indicates that spins are close to an itinerant limit in the largest doping x = 0.7. The dynamic relaxation rates extracted from the LF- aeSR spectra show a three-dimensional diffusive transport. Our combined NMR and ae SR results suggest the occurrence of intriguing spin and charge excitations across the insulator-semimetal transition.
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Collections - College of Natural Sciences > Department of Physics > 1. Journal Articles
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