SQUID NMR studies of the dipole field in ferromagnetic [formula omitted] films

We use SQUID NMR to observe the magnetization of 3 He films with densities between 20 and 24 atoms/ nm 2 in the zero field limit. Ferromagnetism in these nearly 2D Heisenberg exchange systems is stabilized by weak anisotropies. In the ferromagnetic phase, the NMR line becomes very broad and shifts t...

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Bibliographic Details
Published inPhysica. B, Condensed matter Vol. 329; pp. 150 - 151
Main Authors Zhang, Jinshan, Gu, Yuan, White, K.S., Fink, B.R., Gould, C.M., Bozler, H.M.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.05.2003
Subjects
formula omitted
Grafoil
NMR
SQUID
NMR
SQUID
67.70.+n
Grafoil
76.60.−k
3 He
75.70.−1
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Summary:We use SQUID NMR to observe the magnetization of 3 He films with densities between 20 and 24 atoms/ nm 2 in the zero field limit. Ferromagnetism in these nearly 2D Heisenberg exchange systems is stabilized by weak anisotropies. In the ferromagnetic phase, the NMR line becomes very broad and shifts to lower frequencies, consistent with a large dipolar field opposing a perpendicular applied field. Grafoil can be modeled by a Gaussian distribution of platelet angles centered on the normal to the Grafoil plus a randomly distributed set of platelets. Using the spin dynamics of a 2D polarized sheet with reasonable assumptions for the distributions of platelet angles, we show that the magnetization, frequency shift and line shape form a consistent picture of a highly polarized sheet.
ISSN:0921-4526
1873-2135
DOI:10.1016/S0921-4526(02)02023-9