TY - JOUR
T1 - Study of hydrogen diffusion in superprotonic ionic conductors, MHXO4, by μ+SR and QENS
AU - Ikedo, Yutaka
AU - Nozaki, Hiroshi
AU - Harada, Masashi
AU - Sugiyama, Jun
AU - Sato, Taku J.
AU - Matsuo, Yasumitsu
AU - Nishiyama, Kusuo
AU - Lord, James S.
AU - Qiu, Yiming
AU - Copley, John R.D.
N1 - Funding Information:
This work utilized facilities supported in part by the National Science Foundation under Agreement no. DMR-0454672.
PY - 2009/2/21
Y1 - 2009/2/21
N2 - In order to clarify the mechanism of high proton conductivity (σH+) for superprotonic ionic conductors, MHXO4, where M=Cs and Rb, X=S and Se, muon-spin rotation and relaxation (μ+SR) and quasi-elastic neutron scattering (QENS) measurements have been performed at temperatures mainly in the vicinity of Tc, at which MHXO4 undergoes a structural phase transition from a low-T orthorhombic phase (Phase II) to a high-T tetragonal phase (Phase I). The μ+SR experiment shows the presence of muonium (Mu) state even in Phase I only for CsHSO4 (CHS), while no Mu state was found in Phase I of CsHSeO4 (CHSe). Considering the fact that the σH+ in Phase I of CHS is more than 10 times larger that of CHSe, this implies a relationship between the presence of the atomic hydrogen (Mu) state and high σH+ in Phase I of CHS. According to the QENS measurements using a single crystal of CHSe, line shapes of the energy spectra along three crystallographic directions are found to be slightly anisotropic in Phase I, in contrast to the isotropic conductivity reported by AC conductivity measurements.
AB - In order to clarify the mechanism of high proton conductivity (σH+) for superprotonic ionic conductors, MHXO4, where M=Cs and Rb, X=S and Se, muon-spin rotation and relaxation (μ+SR) and quasi-elastic neutron scattering (QENS) measurements have been performed at temperatures mainly in the vicinity of Tc, at which MHXO4 undergoes a structural phase transition from a low-T orthorhombic phase (Phase II) to a high-T tetragonal phase (Phase I). The μ+SR experiment shows the presence of muonium (Mu) state even in Phase I only for CsHSO4 (CHS), while no Mu state was found in Phase I of CsHSeO4 (CHSe). Considering the fact that the σH+ in Phase I of CHS is more than 10 times larger that of CHSe, this implies a relationship between the presence of the atomic hydrogen (Mu) state and high σH+ in Phase I of CHS. According to the QENS measurements using a single crystal of CHSe, line shapes of the energy spectra along three crystallographic directions are found to be slightly anisotropic in Phase I, in contrast to the isotropic conductivity reported by AC conductivity measurements.
KW - Muon spin rotation/relaxation
KW - Proton diffusion
KW - Quasi-elastic neutron scattering
KW - Superprotonic conductors
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U2 - 10.1016/j.nima.2008.11.052
DO - 10.1016/j.nima.2008.11.052
M3 - Article
AN - SCOPUS:59649106043
SN - 0168-9002
VL - 600
SP - 316
EP - 318
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
IS - 1
ER -