Spin transport in dilute, spin-polarized solutions of helium-three in helium-four
We have investigated $\sp3$He spin diffusion in two dilute solutions of $\sp3$He in $\sp4$He, with atomic fraction $x\sp3=1.82\times 10\sp{-3}$ and 6.26 $\times$ 10$\sp{-4}$, spin-polarized by an 8 T field. We do not find evidence that the diffusion coefficient for spins transverse to the average ma...
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ndltd-UMASS-oai-scholarworks.umass.edu-dissertations-71692020-12-02T14:28:17Z Spin transport in dilute, spin-polarized solutions of helium-three in helium-four McAllaster, Donald R We have investigated $\sp3$He spin diffusion in two dilute solutions of $\sp3$He in $\sp4$He, with atomic fraction $x\sp3=1.82\times 10\sp{-3}$ and 6.26 $\times$ 10$\sp{-4}$, spin-polarized by an 8 T field. We do not find evidence that the diffusion coefficient for spins transverse to the average magnetization ($D\sb\perp$) declines or saturates at temperatures down to 0.20$T\sb{\rm F}$, contrary to previous experiment (Gully and Mullin 1984) but in accord with current theory. We have compared our measurements with the latest theory of Jeon and Mullin (1991); our data is mostly in good agreement with their theory if a slightly modified version of a $\sp3$He-$\sp3$He interaction due to Ebner (1967) is used. The congruence between data and theory supports the conclusion that the s-wave approximation to the interaction is not useful for transport calculations even for these rather dilute solutions. There may be an one unresolved discrepancy: our diffusion constant for the lowest concentration at the lowest temperatures is 25% higher than theory predicts. This could be due to a polarization dependance for $D\sb\perp$ or to a modification of the boundary condition by a bound $\sp3$He state, or possibly due to errors in the theoretical calculation. 1992-01-01T08:00:00Z text https://scholarworks.umass.edu/dissertations/AAI9233104 Doctoral Dissertations Available from Proquest ENG ScholarWorks@UMass Amherst Fluid dynamics|Gases|Atoms & subatomic particles |
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ENG |
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Fluid dynamics|Gases|Atoms & subatomic particles |
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Fluid dynamics|Gases|Atoms & subatomic particles McAllaster, Donald R Spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
description |
We have investigated $\sp3$He spin diffusion in two dilute solutions of $\sp3$He in $\sp4$He, with atomic fraction $x\sp3=1.82\times 10\sp{-3}$ and 6.26 $\times$ 10$\sp{-4}$, spin-polarized by an 8 T field. We do not find evidence that the diffusion coefficient for spins transverse to the average magnetization ($D\sb\perp$) declines or saturates at temperatures down to 0.20$T\sb{\rm F}$, contrary to previous experiment (Gully and Mullin 1984) but in accord with current theory. We have compared our measurements with the latest theory of Jeon and Mullin (1991); our data is mostly in good agreement with their theory if a slightly modified version of a $\sp3$He-$\sp3$He interaction due to Ebner (1967) is used. The congruence between data and theory supports the conclusion that the s-wave approximation to the interaction is not useful for transport calculations even for these rather dilute solutions. There may be an one unresolved discrepancy: our diffusion constant for the lowest concentration at the lowest temperatures is 25% higher than theory predicts. This could be due to a polarization dependance for $D\sb\perp$ or to a modification of the boundary condition by a bound $\sp3$He state, or possibly due to errors in the theoretical calculation. |
author |
McAllaster, Donald R |
author_facet |
McAllaster, Donald R |
author_sort |
McAllaster, Donald R |
title |
Spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
title_short |
Spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
title_full |
Spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
title_fullStr |
Spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
title_full_unstemmed |
Spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
title_sort |
spin transport in dilute, spin-polarized solutions of helium-three in helium-four |
publisher |
ScholarWorks@UMass Amherst |
publishDate |
1992 |
url |
https://scholarworks.umass.edu/dissertations/AAI9233104 |
work_keys_str_mv |
AT mcallasterdonaldr spintransportindilutespinpolarizedsolutionsofheliumthreeinheliumfour |
_version_ |
1719363954175639552 |