« Enhanced » magnetism and nuclear ordering of 169Tm spins in TmPO 4

C. Fermon , J.F. Gregg , J.-F. Jacquinot , Y. Roinel , V. Bouffard , G. Fournier , A. Abragam

Ordering of the nuclear spins of 169Tm in TmPO4, caused by their « enhanced » nuclear magnetism, has been produced by Dynamic Nuclear Polarization (D.N.P.) followed by Adiabatic Demagnetization in the Rotating Frame (A.D.R.F.). At positive temperature, when the magnetic field H is parallel to the c-axis of the crystal, the structure is transverse in the rotating frame, thus appearing as rotating at the Larmor frequency in the laboratory frame. This article describes in detail : 1) The influence of the orientation of H on the N.M.R. linewidth, and the experimental procedures used to control this orientation and optimize the D.N.P. results. 2) The nuclear relaxation of 169Tm and 31P when H is almost parallel to c. 3) The 169Tm N.M.R. measurements and the double resonance experiments using 31 P which confirm the nature of the ordered state and are compared to the theoretical predictions (Weiss and R.P.A).

Mots clés: double nuclear magnetic resonance; dynamic nuclear polarisation; magnetic cooling; magnetic structure; NMR line breadth; RPA calculations; thulium compounds

Domaines: Articles anciens

C. Fermon, J.F. Gregg, J.-F. Jacquinot, Y. Roinel, V. Bouffard, et al.. « Enhanced » magnetism and nuclear ordering of 169Tm spins in TmPO 4. Journal de Physique, 1986, 47 (6), pp.1053-1075. ⟨10.1051/jphys:019860047060105300⟩. ⟨jpa-00210282⟩