Diffusion and trapping of muons in aluminum: New experiments and comparison with Kondo theory

Hartmann, O.; Karlsson, E.; Wäckelgrd, Ewa; Wäppling, R.; Richter, D.; Hempelmann, Rolf; Niinikoski, T.

doi:10.1103/physrevb.37.4425

Cited by 73 publications

(33 citation statements)

References 49 publications

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“…1(c) and 1(d) with the binary alloys stored at room temperature suggest rather interesting aspects of muon kinetics with Mg and Si elements: 1) from the spectra at 20 K it is clear that the dissolved Mg in Al well trapped muons, but Si did not. This result is consistent with the previous reports; low temperature depolarization rates depend on impurity elements [10,11]. 2) From the spectra at 300 K there remained deep potentials in 0.5Mg-13d, probably associated with Mg-vacancy clusters trapping muons, but such potentials disappeared in the 0.5Si-12d sample; i.e.…”

Section: Resultssupporting

confidence: 82%

“…Muons have been known to diffuse very fast in pure Al; hence quite dilute (several tens of ppm) impurities, such Mg, Mn, Cu, Ag, etc., produce significant influence on the muon trapping, and thus spin depolarization. The observed temperature variations of depolarization rates of muon spins in Al around 1∼100 K were found to be quite sensitive to the concentrations and elements of impurities [10,11].…”

Section: Introductionmentioning

confidence: 97%

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Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Nishimura¹,

Matsuda²,

Komaki³

et al. 2015

Archives of Metallurgy and Materials

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Zero-field muon spin relaxation experiments were carried out with Al-1.6%Mg 2 Si, Al-0.5%Mg, and Al-0.5%Si alloys. Observed relaxation spectra were compared with the calculated relaxation functions based on the Monte Carlo simulation to extract the dipolar width (∆), trapping (ν t ), and detrapping rates (ν d ), with the initially trapped muon fraction (P 0 ). The fitting analysis has elucidated that the muon trapping rates depended on the heat treatment and solute concentrations. The dissolved Mg in Al dominated the ν t at lower temperatures below 120 K, therefore the similar temperature variations of ν t were observed with the samples mixed with Mg. The ν t around 200 K remarkably reflected the heat treatment effect on the samples, and the largest ν t value was found with the sample annealed at 100 • C among Al-1.6%Mg 2 Si alloys. The as-quenched Al-0.5%Si sample showed significant ν t values between 80 and 280 K relating with Si-vacancy clusters, but such clusters disappeared with the natural aged Al-0.5%Si sample.Keywords: Al-Mg-Si alloys, muon spin relaxation, vacancy Stopy Al-1,6%Mg 2 Si, Al-0,5%Mg i Al-0,5%S poddano badaniu relaksacji spinowej mionów w zerowym polu magnetycznym. Obserwowane widma relaksacyjne porównano z funkcjami relaksacji obliczonymi przy wykorzystaniu symulacji Monte Carlo w celu otrzymania informacji o szerokości dipolarnej ∆ (ang. dipolar width) oraz szybkości uwięzienia ν t (ang. trapping) i uwolnienia ν d (ang. detrapping) z pierwotnie związaną frakcją mionów (P 0 ). Z przeprowadzonej analizy wynika, że szybkość uwięzienia mionów zależy od zastosowanej uprzednio obróbki cieplnej oraz stężenia pierwiastków domieszki. W przypadku Mg rozpuszczonego w osnowie Al dominowała szybkość ν t w temperaturach poniżej 120 K, dlatego też w próbkach domieszkowanych Mg obserwowano podobne odchylenia temperaturowe szybkości ν t . Szybkość ν t w temperaturze około 200 K doskonale ukazuje wpływ zastosowanej obróbki cieplnej na omawiane próbki, z których najwyższą wartość ν t wykazały te wyżarzane w 100 • C spośród stopów Al-1,6%Mg 2 Si. Próbka Al-0,5%Si wykazała znaczące wartości ν t pomiędzy temperaturami 80 a 280 K wskazujące na aglomeracje wakancji Si, które jednak zanikają po naturalnym starzeniu stopu Al-0.5%Si.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 97%

Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Nishimura¹,

Matsuda²,

Komaki³

et al. 2015

Archives of Metallurgy and Materials

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“…С этим может быть связана трудность в иденти фикации типа междоузлия, в котором локализуется мюон. Если в области высоких температур тип меж доузлия определяется однозначно, то при низких температурах этого сделать не удается [28], или дан ные эксперимента интерпретируются как изменение типа междоузлия [29][30][31].…”

Section: 22unclassified

“…А л ю м и н и й . Алюминий -металл, наиболее исследованный методом SR [26,30,31,[48][49][50][51][52][53][54][55][56]. Его отличительной чертой является отсутствие наблю даемой релаксации в чистом алюминии.…”

Section: анализ экспериментальных данныхunclassified

“…Различная природа минимумов, в которых нахо дится мюон при температурах выше и ниже Т min , подтверждается различием в величине градиента электрического поля, действующего на мюон в ло вушке [30], что интерпретируется обычно, как пере ход мюона из тетрапоры в октапору [30,31], но мо жет быть связано с тем, что менее глубокий минимум расположен дальше от дефекта, играющего роль ло вушки [30].…”

Section: анализ экспериментальных данныхunclassified

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Muon spin relaxation in crystals with defects

Morozov¹,

Сигов²

1993

Usp. Fiz. Nauk

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Tunneling in Metals as a Dissipative Quantum Process

Kondo

1991

Ber Bunsenges Phys Chem

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There are two characteristic energies for the proton in metals: the orbiting frequency within a site (hw,) and the tunneling integral between neighbouring sites (A). Since typically h a o is lo00 K and A less than 10 K, the temperature range defined by hwo % kT % A is experimentally accessible. This is peculiar to the proton and proton isotopes. -Low-energy excitations of the metal electrons cannot follow instantaneously the orbiting motion of the proton in a single well. They are equal to those when the proton potential is averaged over the proton wave function representing the orbiting motion. When the proton tunnels to another site, the low-energy excitations must be rearranged to correspond to the new proton position. Then the tunneling integral of the proton acquires a factor of the overlap integral between two electronic wave functions corresponding to two proton positions. This integral turns out to be much smaller than unity and depends on a power of the temperature when hwo $ kT $ A. This power law is a result of the non-adiabatic response of the metal electrons to proton motion. Such a power law will manifest itself in diffusion constant of the proton or proton isotopes.

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Diffusion and trapping of muons in aluminum: New experiments and comparison with Kondo theory

Cited by 73 publications

References 49 publications

Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Solute-Vacancy Clustering In Al-Mg-Si Alloys Studied By Muon Spin Relaxation Technique

Muon spin relaxation in crystals with defects

Tunneling in Metals as a Dissipative Quantum Process

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