Landmarks in Magnetism of Solid ³He
1. 1950—First ³He became available.
2. 1950—Pomeranchuk effect: dipole-dipole interactions, TC ~ 10-7 K, Ssolid = Sspins = R ln (2I + 1) = R ln 2 > Sliquid at low T, melting pressure minimum; Pomeranchuk effect, cool by compressing liquid ³He. I. Pomeranchuk, Zh. Eksp.Teor. Fiz. 20, 919 (1950).
3. 1958—NMR experiments to measure Χ = C/(T-θ) θ<0 antiferro; θ>0 ferromag. (inconclusive).
4. 1959—Melting pressure minimum measured using in situ pressure gauge. J. Baum, D.F. Brewer, J.G. Daunt, and D.O Edwards, Phys. Rev. Lett. 3, 127 (1959).
5. 1959—"Exchange interaction" J, caused by zero-point motion, overlap of wave functions. Predicted TC ~ 10-2- 10-1 K. N. Bernardes and I. Primakoff, Phys. Rev. Lett. 2, 290 (1959).
6. 1960-65—NMR measurements of T1 and T2, [J(v)] ~ 0.7 k (mK) at Pmelt; strong v-dependence, J ~ v17. R.C. Richardson, E. Hunt, and H. Meyer, Phys. Rev. 138, A1326 (1965). R.A. Guyer, R.C. Richardson, and L.I. Zane, Rev. Mod. Phys. 43, 532 (1971).
7. 1965—Pomeranchuk effect used to cool ³He. Yu. D. Anufriyev, Zh. Eksp. Teor. Fiz. Pis. Red. 1, 1 (1965).
8. 1965—Multiple-exchange interactions, Jeven N < 0, antiferromagnetism; Jodd N > 0, ferromagnetism. D. Thouless, Proc. Phys. Soc. 86, 893 (1965).
Hex = S Jn (-1)P Pn
9. 1967—Thermodynamic determination of [J(v)] from Pv(T). Confirmed NMR values. M.F. Panczyk, R.C. Scribner, G.C. Straty, and E.D. Adams, Phys. Rev. Lett. 19, 1102 (1967); M.F. Panczyk and E.D. Adams, Phys. Rev. 187, 321 (1969).
10. 1967—Calculations of Jnn for Heisenberg nearest neighbor Hamiltonian, HNN. Only nn interactions thought to be important, second-order TC ~ 2 mK expected. J.H. Hetherington, W.J. Mullin, and L.H. Nosanow, Phys. Rev. 154, 175 (1967).
11. 1969—Susceptibility showed θ<0. Antiferro. expected at TC = 2 mK. P.B. Pipes and W.M. Fairbank, Phys. Rev. Lett. 23, 520 (1969); W.P. Kirk, E.B. Osgood, and M. Garber, Phys. Rev. Lett. 23, 833 (1969); J.R. Sites, D.D. Osheroff, R.C. Richardson, and D.M. Lee, Phys. Rev. Lett. 23, 836 (1969). [Fig. from Pipes and Fairbank.]
12. 1971—HNN-model shown to be inadequate by Pv(T,B); multiple-exchange interactions required. W.P. Kirk and E.D. Adams, Phys. Rev. Lett. 27, 392 (1971).
13. 1974—Discovery of first-order TN ~ 1.0 mK, ΔS = 0.4 R ln 2. (The low-field phase, LFP.) W.P. Halperin C.N. Archie, F.B. Rasmussen, R.A. Buhrman, and R.C. Richardson, Phys. Rev. Lett. 32, 927 (1974).
14. 1975—High-field ordered phase discovered for B > 0.4 T. R.B. Kummer, E.D. Adams, W.P. Kirk, A.S. Greenberg, and D.M. Lee, Phys. Rev. Lett. 34, 517 (1975). [Fig. from W. Ni, J.S. Xia, and E.D. Adams, Phys. Rev. B 50, 336 (1994).]
15. 1975—Multiple- exchange proposed. J.H. Hetherington and F.D.C. Willard, Phys. Rev. Lett. 35, 1442 (1975). M. Roger, J.H. Hetherington, and J.M. Delrieu, Rev. Mod. Phys. 55, 1 (1983).
16. 1977—Drop in magnetization in LFP at TN by 2/3, antiferromagnetism confirmed. T.C. Prewitt and J.M. Goodkind, Phys. Rev. Lett. 39, 1283 (1977). [Fig. from T. Hata, S. Yamasaki, T. Kodama, and T. Shigi, J. Low Temp. Phys. 71, 193 (1988).]
17. 1980—NMR in ordered phases. LFP spectrum shows tetragonal U2D2 structure; small Δν in HFP shows cubic structure. D.D. Osheroff, M.C. Cross, and D.S. Fisher, Phys. Rev. Lett. 44, 792 (1980); E.D. Adams, E.A. Schuberth, G.E. Haas, and D.M. Bakayler, Phys. Rev. Lett. 44, 789 (1980). [Fig. from Osheroff et al.]
18. 1977—Drop in magnetization in LFP at TN by 2/3, antiferromagnetism confirmed. T.C. Prewitt and J.M. Goodkind, Phys. Rev. Lett. 39, 1283 (1977). [Fig. from T. Hata, S. Yamasaki, T. Kodama, and T. Shigi, J. Low Temp. Phys. 71, 193 (1988).]
19. 1985—Magnetization measurements in high-pressure hcp phase show ferromagnetic tendency due to triple exchange. Y. Takano, N. Nishida, Y. Miura, H. Fukuyama, H. Ishimoto, S. Ogawa, T. Hata, and T. Shigi, Phys. Rev. Lett. 55, 1490 (1985). [Fig. from H. Yano, H. Kondo, T. Suzuki, Y. Minamide, T. Kato, Y. Miura, and T. Mamiya, Phys. Rev. Lett, 65, 3401 (1990).]
20. 1987—Monte Carlo calculations of exchange processes out to six particles. D.M. Ceperley and G. Jacucci, Phys. Rev. Lett. 58, 1648 (1987).
21. 1987—Magnetization measured to B = 11 T, Bc2 extrapolated to 22 T. D.D. Osheroff, H. Godfrin, and R. Ruel, Phys. Rev. Lett. 58, 2458 (1987).
22. 1990—Entire B-T ordered phase determined for v = 22.7 cm3/mole. H. Fukuyama, T. Fukuda, T. Okamoto, H. Akimoto, H. Ishimoto and S.Ogawa, Physica B 169, 197 (1991).
23. 1996—Ferromagnetic ordering in hcp phase verified in cascade two-stage demagnetization. T. Lang, P.L. Moyland, D.A. Sergatskov, E.D. Adams, and T. Takano, Phys. Rev. Lett. 77, 322 (1996).
