Competing 4 f-electron dynamics in Ce(Ru1-xFex)(2)Al-10 (0
(2013) In Physical Review B (Condensed Matter and Materials Physics) 87(22).- Abstract
- We have carried out muon spin relaxation (mu SR), neutron diffraction, and inelastic neutron scattering (INS) investigations on polycrystalline samples of Ce(Ru1-xFex)(2)Al-10 (x = 0, 0.3, 0.5, 0.8, and 1) to investigate the nature of the ground state (magnetic ordered versus paramagnetic) and the origin of the spin-gap formation as evident from the bulk measurements in the end members. Our zero-field mu SR spectra clearly reveal coherent two-frequency oscillations at low temperature in x = 0, 0.3, and 0.5 samples, which confirm the long-range magnetic ordering of the Ce moment with Neel temperature T-N = 27, 26, and 21 K, respectively. On the other hand, the mu SR spectra of x = 0.8 and x = 1 down to 1.4 K and 0.045 K, respectively,... (More)
- We have carried out muon spin relaxation (mu SR), neutron diffraction, and inelastic neutron scattering (INS) investigations on polycrystalline samples of Ce(Ru1-xFex)(2)Al-10 (x = 0, 0.3, 0.5, 0.8, and 1) to investigate the nature of the ground state (magnetic ordered versus paramagnetic) and the origin of the spin-gap formation as evident from the bulk measurements in the end members. Our zero-field mu SR spectra clearly reveal coherent two-frequency oscillations at low temperature in x = 0, 0.3, and 0.5 samples, which confirm the long-range magnetic ordering of the Ce moment with Neel temperature T-N = 27, 26, and 21 K, respectively. On the other hand, the mu SR spectra of x = 0.8 and x = 1 down to 1.4 K and 0.045 K, respectively, exhibit a temperature-independent Kubo-Toyabe term, confirming a paramagnetic ground state. The long-range magnetic ordering in x = 0.5 below 21 K has been confirmed through the neutron diffraction study. INS measurements of x = 0 clearly reveal the presence of a sharp inelastic excitation near 8 meV between 5 K and 26 K, due to an opening of a gap in the spin excitation spectrum, which transforms into a broad response at and above 30 K. Interestingly, at 4.5 K, the spin-gap excitation broadens in x = 0.3 and exhibits two clear peaks at 8.4(3) and 12.0(5) meV in x = 0.5. In the x = 0.8 sample, which remains paramagnetic down to 1.2 K, there is a clear signature of a spin gap of 10-12 meV at 7 K, with a strong wave-vector-dependent intensity. Evidence of a spin gap of 12.5(5) meV has also been found in x = 1. The observation of a spin gap in the paramagnetic samples (x = 0.8 and 1) is an interesting finding in this study, and it challenges our understanding of the origin of the semiconducting gap in CeT2Al10 (T = Ru and Os) compounds in terms of a hybridization gap opening only a small part of the Fermi surface, gapped spin waves, or a spin-dimer gap. (Less)
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- author
- organization
- publishing date
- 2013
- type
- Contribution to journal
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- published
- subject
- in
- Physical Review B (Condensed Matter and Materials Physics)
- volume
- 87
- issue
- 22
- article number
- 224415
- publisher
- American Physical Society
- external identifiers
-
- wos:000320759200002
- scopus:84879713721
- ISSN
- 1098-0121
- DOI
- 10.1103/PhysRevB.87.224415
- language
- English
- LU publication?
- yes
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- 8f5f444c-f8c8-4e0c-8c8c-9811c8776bd8 (old id 3979764)
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@article{8f5f444c-f8c8-4e0c-8c8c-9811c8776bd8,
abstract = {{We have carried out muon spin relaxation (mu SR), neutron diffraction, and inelastic neutron scattering (INS) investigations on polycrystalline samples of Ce(Ru1-xFex)(2)Al-10 (x = 0, 0.3, 0.5, 0.8, and 1) to investigate the nature of the ground state (magnetic ordered versus paramagnetic) and the origin of the spin-gap formation as evident from the bulk measurements in the end members. Our zero-field mu SR spectra clearly reveal coherent two-frequency oscillations at low temperature in x = 0, 0.3, and 0.5 samples, which confirm the long-range magnetic ordering of the Ce moment with Neel temperature T-N = 27, 26, and 21 K, respectively. On the other hand, the mu SR spectra of x = 0.8 and x = 1 down to 1.4 K and 0.045 K, respectively, exhibit a temperature-independent Kubo-Toyabe term, confirming a paramagnetic ground state. The long-range magnetic ordering in x = 0.5 below 21 K has been confirmed through the neutron diffraction study. INS measurements of x = 0 clearly reveal the presence of a sharp inelastic excitation near 8 meV between 5 K and 26 K, due to an opening of a gap in the spin excitation spectrum, which transforms into a broad response at and above 30 K. Interestingly, at 4.5 K, the spin-gap excitation broadens in x = 0.3 and exhibits two clear peaks at 8.4(3) and 12.0(5) meV in x = 0.5. In the x = 0.8 sample, which remains paramagnetic down to 1.2 K, there is a clear signature of a spin gap of 10-12 meV at 7 K, with a strong wave-vector-dependent intensity. Evidence of a spin gap of 12.5(5) meV has also been found in x = 1. The observation of a spin gap in the paramagnetic samples (x = 0.8 and 1) is an interesting finding in this study, and it challenges our understanding of the origin of the semiconducting gap in CeT2Al10 (T = Ru and Os) compounds in terms of a hybridization gap opening only a small part of the Fermi surface, gapped spin waves, or a spin-dimer gap.}},
author = {{Adroja, D. T. and Hillier, A. D. and Muro, Y. and Kajino, J. and Takabatake, T. and Peratheepan, P. and Strydom, A. M. and Deen, Pascale and Demmel, F. and Stewart, J. R. and Taylor, J. W. and Smith, R. I. and Ramos, S. and Adams, M. A.}},
issn = {{1098-0121}},
language = {{eng}},
number = {{22}},
publisher = {{American Physical Society}},
series = {{Physical Review B (Condensed Matter and Materials Physics)}},
title = {{Competing 4 f-electron dynamics in Ce(Ru1-xFex)(2)Al-10 (0}},
url = {{http://dx.doi.org/10.1103/PhysRevB.87.224415}},
doi = {{10.1103/PhysRevB.87.224415}},
volume = {{87}},
year = {{2013}},
}