T T4!cesn3T42 K
4. Summary
This chapter deals with valence-fluctuation and heavy-fermion 4f systems, such as Ce, Sin, Eu, Tm and Yb alloys and compounds. Sections 1 and 2 summarize the most important physical properties of these systems, based on the main theoretical results achieved so far and on representative data.
In the main part (section 3) we summarize neutron scattering data of VF and H F systems. By means of neutrons one can measure the magnetic structure of a system (elastic magnetic scattering) and magnetic and non-magnetic excitations such as relaxational modes (quasi-elastic excitations), magnons, crystal field, and spin orbit transitions, and phonons. Some of these excitations have been observed in all VF or H F systems. Both VF and H F systems exhibit a quasi-elastic line due to spin fluctuations or the Kondo effect. Both expressions are used synonymously, but in VF systems the quasi-elastic line is quite broad, corresponding to a high characteristic energy, and is fairly temperature independent. Here one speaks in general about spin fluctuations. In H F systems the quasi-elastic line is narrower, temperature dependent, and has, at low temperatures, an halfwidth ½F-~ kB T~. A typical quasi-elastic line can be fitted by a Lorentzian and corresponds to a single relaxation time. In most HF compounds the line becomes Q-dependent at low temperatures, indicating spin correlations that at still lower temperatures often lead to magnetic order. These spin correlations, on the other hand, lead already to deviations from the Lorentz shape above the spin-ordering temperature. In VF compounds spin correlations do not play a role, but the high-temperature quasi-elastic line also changes shape and becomes narrower and inelastic at low temperatures.
Ce-based H F systems have been investigated by many groups, whereas few data exist for the corresponding VF systems and for Yb-, Sm-, Eu-, and Tm-based VF and H F systems. As a consequence, our survey over Ce-based VF and Yb, Sm, Eu, and Tm systems is rather complete, whereas for Ce-based H F systems we could only select representative examples. Part of this strong research activity on Ce compounds is due to the fact that CeCu2Si2 becomes superconducting, and it is an enormous challenge to find other superconducting H F systems. In addition, one has in these systems a variety of magnetic structures, such as ferromagnetic, antiferromagnetic and spiral order and metamagnetism. In many cases the detection of these structures is hampered by moments that are strongly reduced by the K o n d o effect.
In addition to the K o n d o effect one has in H F systems strong crystal field effects, and the corresponding 4f-levels can be determined by neutron scattering experiments.
The interplay between Kondo and CF effects varies from system to system, and the corresponding information is part of the content of this chapter. Since in H F systems the K o n d o temperature is typically rather small, one observes at low temperature mainly the properties of the lowest CF level.
Valence fluctuations couple to phonons, and our review gives a rather complete survey of the corresponding anomalies. In addition, one has phonon anomalies due to the C F - p h o n o n interaction, since a lattice deformation around an R ion modifies the crystalline electric field. Finally, we mention the spin orbit interaction, which is
VF AND HF 4f SYSTEMS 97 modified in VF and HF systems due to the hybridization between f and conduction electrons. The few neutron scattering experiments on spin-orbit transitions in VF and HF systems show unexpected splittings, line shifts, and line broadenings if compared to the free-ion case.
References
Alekseev, P.A., A.S. Ivanov, B. Dorner, H.
Schober, K.A. Kikoin, A.S. Mishchenko, V.N.
Lazukov, E.S. Konovalova, Y.B. Paderno, A.Y.
Rumyantscv and I.P. Sadikov, 1989, Europhys.
Lett. 10, 457.
Alekseev, P.A., A.S. Ivanov, V.N. Lazukov, I.P.
Sadikov and A. Severing, 1992, Physica B 180 + 181, 281.
Aliev, F.G., N.B. Brandt, V.V. Moshchalkov and S.M. Chudinov, 1984, J. Low Temp. Phys. 57, 61.
Amato, A., D. Jaccard, J. Flouquet, F. Lapierre, J.L. Tholence, R.A. Fisher, S.E. Lacy, J.A. Olsen and N.E. Phillips, 1987, J. Low Temp. Phys.
68, 371.
Andrei, N., and J.H. Loewenstein, 1981, Phys.
Rev. Len. 46, 356.
Andrei, N., K. Furuya and J.H. Loewenstein, 1983, Rev. Mod. Phys. 55, 33t.
Andres, K., J.E. Graebner and H.R. Ott, 1975, Phys. Rev. Lett. 35, 1779.
Asano, H., M, Umino, Y. Onuki, T. Komatsu- bara, F. Izumi and N. Watanabe, 1986, J. Phys.
Soc. Jpn. 55, 454.
Auerbach, A., and K. Levin, 1986a, Phys. Rev.
Len. 57, 877.
Auerbach, A., and K. Levin, 1986b, Phys. Rev. B 34, 3524.
Auerbach, A., J.tt. Kim and K. Levin, 1987, Phys- ica B 148, 50.
Auerbach, A., J.H. Kim and K. Levin, 1988, Phys.
Rev. Lett. 60, 623.
Ayache, C., J. Beillc, E. Bonjour, R. Calemczuk, G. Creuzet, D. Gignoux, A. Najib, D. Schmitt, J. Voiron and M. Zerguine, 1987, J. Magn. &
Magn. Mater. 63-64, 329.
Baer, Y., and W.-D. Schneider, 1987, in: Hand- book on the Physics and Chemistry of Rare Earths, Vol. I0, eds K.A. Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 1.
Balakrishnan, G., D. Mck. Paul and N.R. Bern- hoeft, 1989, Physica B 156-157, 815.
Barbara, B., J.X. Boucherle, J.L. Bouevoz, M.F.
Rossignol and J. Schweizer, 1977, Solid State Commun. 24, 481.
Barbara, B., M.F. Rossignol, J.N. Boucherle, J. Schweizer and J.L. Bouevoz, 1979, J. Appl.
Phys. 50, 2300.
Barbara, B., M.F. Rossignol, J.X. Boucherle and C. Vettier, 1980, Phys. Rev. Lett. 45, 938.
Batlogg, B., H.R. Ott, E. Kaldis, W. Th6ni and P. Wachter, 1979, Phys. Rev. B 19, 247.
Bauchspiess, K.R., W. Boksch, E. Holland- Moritz, H. Launois, R. Pott and D. Wohlleben, 1982, in: Valence Fluctuations in Solids, eds L.M. Falicov, W. Hanke and M.B. Maple (North-Holland, Amsterdam) p. 417.
Bennemann, K.H., and M. Avignon, 1979, Solid State Commun. 31,645.
Benoit, A., J.X. Boucherle, P. Convert, J. Flouquet, J. Palleau and J. Schweizer, 1980, Solid State Commun. 34, 293.
Benoit, A., J.X. Boucherle, J. Flouquet, J. Sakurai and J. Schweizer, 1985, J. Magn. & Magn.
Mater. 47-48, 149.
Berton, A., J. Chassy, B. Cornut, J. Flouquet, J. Odin, J. Peyard and F'. Holtzberg, 1981, Phys.
Rev. B 23, 3504.
Besnus, M.J., J.P. Kappler, P. Lehmann and A.
Meyer, 1985, Solid State Commun. 55, 779.
Besnus, M.J., M. Benakki, A. Braghta, H. Danan, G. Fischer, J.P. Kappler, A. Meyer and P. Pan- issod, 1988, J. Magn. & Magn. Mater. 76-77, 471.
Bickers, N.E., 1987, Rev. Mod. Phys. 59, 846.
Bickers, N.E., D.L. Cox and J.W. Wilkins, 1987, Phys. Rev. B 36, 2036.
Bilz, H., G. Gfintherodt, W. Kleppmann and W.
Kress, 1979, Phys. Rev. Lett. 43, 1988.
Bjerrum-Moller, H., S.M. Shapiro and R.J. Birgeneau, 1977, Phys. Rev. Lett. 39, 1021.
Blaschko, O., G. Krexner, L. Pintschovius, W.
Assmus and G. Ernst, 1984, Solid State Com- mun. 51, 971.
B6hm, A., R. Caspary, U. Habel, L. Pawlak, A.
Zuber, F. Steglich and A. Loidl, 1988, J. Magn.
& Magn. Mater. 76-77, 150.
Bonnet, M., J.X. Boucherle, J. Flouquet, F.
Holtzberg, D. Jaccard, J. Schweizer and A. S t u nault, 1986, Physica B 136, 428.
98 M. LOEWENHAUPT and K.H. FISCHER Bonville, P., and J.A. Hodges, 1985, J. Magn. &
Magn. Mater. 47-48, 152.
Bonville, P., J.A. Hodges, F. Hulliger, P. Imbert, G. Jehanno, J.B. Marimon da Cunha and H.R.
Ott, 1988, J. Magn. & Magn. Mater. 76-77, 473.
Bonville, P., J.A. Hodges, P. lmbert, D. Jaccard, J. Sierro, M.J. Besnus and A. Meyer, 1990, Physica B 163, 347.
Bonville, P., J. Hammann, J.A. Hodges, P. Imbert, G. Jehanno, M.J. Besnus and A. Meyer, 1991, Z. Phys. B 82, 267.
Borsa, F., and G. Olcese, 1973, Phys. Star. Solidi (a) 17, 631.
Boucherle, J.X., and J. Schweizer, 1985, Physica B 130, 337.
Boucherle, J.X., J.L. Buevoz, S. Horn, M. Loewen- haupt, H. Scheuer, J. Schweizer and F. Steglich, 1981, Solid State Commun. 38, 669.
Boucherle, J.X., J. Flouquet, Y. Lassailly, J. Palleau and J. Schweizer, 1983, J. Magn. &
Magn. Mater. 31-34, 409.
Boucherle, J.X., G. Fillion, J. Flouquet, F. Givord, P. Lejay and J. Schweizer, 1990, Physica B 163, 635.
Bredl, C.D., 1987, J. Magn. & Magn. Mater.
63-64, 355.
Burghardt, P., K.A. Gschneidner Jr, D.C.
Koskenmaki, D.K. Finnemore, J.O. Moorman, S. Legvold, C. Stassis and T.A. Vyrostek, 1976, Phys. Rev. B 14, 2995.
Buyers, W.J.L., 1986, Physica B 137, 53.
Capellmann, H., P.J. Brown, S.M. Johnson, K.R.A. Ziebeck and J.G. Booth, 1985, J. Magn.
& Magn. Mater. 49, 137.
Chattopadhyay, T., H. v. L6hneysen, T. Trapp- mann and M. Loewenhaupt, 1990, Z. Phys. B 80, 159.
Coleman, P., 1984, Phys. Rev. B 29, 3035.
Coleman, P., 1987a, Phys. Rev. B 35, 5072.
Coleman, P., 1987b, J. Magn. & Magn. Mater.
63-64, 245.
Cox, D.L., and N. Grewe, 1988, Z. Phys. B 71, 321.
Cox, D.L., N.E. Bickers and J.W. Wilkins, 1986, J. Magn. & Magn. Mater. 54-57, 333.
Cromer, D.T., A.C. Larson and R.B. Roof, 1960, Acta Crystallogr. 13, 913.
Currat, R., R.G. Lloyd, P.W. Mitchell, A.P. Mur- ani and J.W. Ross, 1989, Physica B 156-157, 812.
Czycholl, G., 1982, Phys. Rev. B 25, 3413.
Debray, D., R. Kahn, D i . Decker, A. Werner, M. Loewenhaupt, E. Holland-Moritz and D.K.
Ray, 1981, in: Valence Fluctuations in Solids, eds L.M. Falicov, W. Hanke and M.B. Maple (North-Holland, Amsterdam) p. 183.
Desgranges, H.-U., and J.W. Rasul, 1985, Phys.
Rev. B 32, 6100.
Dhar, S.K., K.A. Gschneidner Jr, W.H. Lee, P.
Klavins and R.N. Shelton, 1987, Phys. Rev. B 36, 341.
Dijkman, W.H., F.R. de Boer, P.F. de Chatel and J. Aarts, 1980, J. Magn. & Magn. Mater. 15-18, 970~
Doniach, S., 1977, Physica B 91,231.
Doniach, S., 1987, Phys. Rev. B 35, 1814.
D6nni, A., P. Fischer, A. Furrer, P. Bonville, F.
Hulliger and H.R. Ott, 1990a, Z. Phys. B 81, 83.
D6nni, A., P. Fischer, A. Furrer, W. Bacsa and P. Wachter, 1990b, Z. Phys. B 80, 269.
D6nni, A., A. Furrer, P. Fischer, F. Hulliger, P.
Wachter and H.R. Ott, 1990c, J. Magn. &
Magn. Mater. 90-91, 143.
Dormann, E., 1991, in: Handbook on the Physics and Chemistry of Rare Earths, Vol. 14, eds K.A.
Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 63.
Effantin, J.M., J. Rossat-Mignod, P. Burlet, H.
Bartholin, S. Kunii and T. Kasuya, 1985, J. Magn. & Magn. Mater. 47-48, 145.
Eiling, A., and J.S. Schilling, 198I, Phys. Rev.
Lett. 46, 364.
Elenbaas, R.A., C.J. Schinkcl and C.J.M. van Deu- dekom, 1980, J. Magn. & Magn. Mater. 15-18, 979.
Elschner, B., and M. Schlott, 1988, J. Magn. &
Magn. Mater. 76-77, 444.
Erkelens, W.A.C., L.P. Regnault, P. Burlet, J. Rossat-Mignod, S. Kunii and T. Kasuya, 1987, J. Magn. & Magn. Mater. 63-64, 61.
Fedro, A.J., and S.K. Sinha, 1981, in: Valence Fluctuations in Solids, eds L. M. Falicov, W.
Hanke and M. B. Maple (North-Holland, Amsterdam) p. 329.
Felner, I., I. Nowik, D. Vaknin, U. Potzel, J. Moser, G.M. Kalvius, G. Wortmann, G.
Schmiester, G. Hilscher, E. Gratz, C. Schmitzer, N. Pillmayr, K.G. Prasad, H. de Waard and H.
Pinto, 1987, Phys. Rev. B 35, 6956.
Felten, R., G. Weber and H. Rietschel, 1987, J. Magn. & Magn. Mater. 63-64, 383.
Fillion, G., R.M. Galera, D. Givord, J. Pierre, J. Schweizer and C. Vettier, 1985, J. Appl. Phys.
57, 3179.
Fischer, K.H., 1970, Springer Tracts Mod. Phys.
54, 1.
VF AND H F 4f SYSTEMS 99 Fischer, K.H., t989a, Z. Phys. B 74, 475.
Fischer, K.H., 1989b, Z. Phys. B 76, 315.
Forgan, E.M., B.D. Rainford, S.L. Lee, J.S. Abell and Y. Bi, 1990, J. Phys.: Condens. Matter 2, 10211.
Franz, W., E. Griessel, F. Steglich and D.
Wohlleben, I978, Z. Phys. B 31, 7.
Frick, B., M. Loewenhaupt, D. Debray and W.
Just, 1983, Z. Phys. B 52, 223.
Fulde, P., and M. Loewenhaupt, 1986, Adv. Phys.
34, 589.
Fulde, P., J. Keller and G. Zwicknagl, 1988, Solid State Phys. 41, 1.
Furrer, A., W. Bfihrer and P. Wachter, 1981, Solid State Commun. 40, 1011.
Galera, R.M., D. Givord, J. Pierre, A.P. Murani, J. Schweizer, C. Vettier and K.R.A. Ziebeck, 1985a, J. Magn. & Magn. Mater. 52, 103.
Galera, R.M., D. Givord, J. Pierre, A.P. Murani, C. Vettier and K.R.A. Ziebeck, 1985b, J. Magn.
& Magn. Mater. 47-48, 139.
Galera, R.M., A.P. Murani, J. Pierre and K.R.A.
Ziebeck, 1987, J. Magn. & Magn. Mater. 63-64, 594.
Gatera, R.M., A.P. Murani and J. Pierre, 1989, Physica B 156-157, 801.
Germann, A., and H. v. L6hneysen, 1989, Euro- phys. Lett. 9, 367.
Gibbons, E.P., E.M. Forgan and K.A. McEwen, 1987, J. Phys. F 17, L101.
Gibbons, E.P., E.M. Forgan, K.A. McEwen and A.P. Murani, 1989, Physica B 156-157, 777.
Gignoux, D., D. Schmitt and M. Zerguine, 1988a, Phys. Rev. B 37, 9882.
Gignoux, D., D. Schmitt, M. Zerguine and A.P.
Murani, 1988b, J. Magn. & Magn. Mater.
76-77, 401.
Goldman, A.I., 1985, Physica B 135, 9.
Gompf, F., E. Gering, B. Renker, H. Rietschel, U.
Rauchschwalbe and F. Steglich, 1987, J. Magn.
& Magn. Mater. 63-64, 344.
Goremychkin, E.A., and R. Osborn, 1991a, report RAL-91-072 and to be published in Phys.
Rev. B.
Goremychkin, E.A., and R. Osborn, 1991b, report RAL-91-073 and to be published in Phys.
Rev. B.
Gratz, E., E. Bauer, B. Barbara, S. Zemirli, F.
Steglich, C.D. Bredl and W. Lieke, 1985, J. Phys. F 15, 1975.
Grewe, N., 1983, Z. Phys. B 52, 193; 53, 2711.
Grewe, N., 1988, Solid State Commun. 66, 1053.
Grewe, N., and P. Entel, 1979, Z. Phys. B 33, 331.
Grewe, N., and F. Steglich, 1991, in: Handbook
on the Physics and Chemistry of Rare Earths, Vol. 14, eds K.A. Gschneidner Jr and L. Eyring (North-ttolland, Amsterdam) p. 343.
Grewe, N., and B. Welslau, 1988, Solid State Commun. 65, 437.
Grewe, N., H.J. Leder and P. Entel, 1980, in:
Festk6rperplobleme XX. Advances in Solid State Physics, ed. H. Treusch (Vieweg, Braunschweig) p. 413.
Grewe, N., T. Pruschke and H. Keiter, 1988, Z.
Phys. B 71, 75.
Grier, B.H., S.M. Shapiro, C.F. Majkrzak and R.D. Parks, 1980, Phys. Rev. Lett. 45, 666.
Grier, B.H., R.D. Parks, S.M. Shapiro and C.F.
Majkrzak, 1981, Phys. Rev. B 24, 6242.
Grier, B.H., J.M. Lawrence, V. Murgai and R.D.
Parks, 1984, Phys. Rev. B 29, 2664.
Grier, B.H., J.M. Lawrence, S. Horn and J.D.
Thompson, 1988, J. Phys. C 21, 1099.
Grtiner, G., and A. Zawadowski, 1974, Rep.
Progr. Phys. 37, 1497.
Gschneidner Jr, K.A., and A.H. Daane, 1988, in:
Handbook on the Physics and Chemistry of Rare Earths, Vol. 1 t, eds K.A. Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 409.
Gunnarsson, O., and K. Sch6nhammer, 1987, in:
Handbook on the Physics and Chemistry of Rare Earths, Vol. 10, eds K.A. Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 103.
Haen, P., J. Flouquet, F. Lapierre, P. Lejay, J.M.
Mignot, A. Ponchet and J. Voiron, 1987, J. Magn. & Magn. Mater. 63-64, 320.
Harris, I.R., M. Norman and W.E. Gardner, 1972, J. Less-Common Met. 29, 299.
Havinga, E.E., H. Damsma and M.H. Van- maaren, 1970, J. Phys. & Chem. Solids 31, 2653.
Havinga, E.E., K.H.J. Buschow and H.J. van Daal, 1973, Solid State Commun. 13, 621.
Herbst, J.E., R.E. Watson and J.W. Witkins, 1978, Phys. Rev. B 17, 3089.
Hiebl, K., and P. Rogl, 1985, J. Magn. & Magn.
Mater. 50, 39.
Hiebl, K., C. Howarth, P. Rogl and M.J. Sienko, 1983, J. Magn. & Magn. Mater. 37, 287.
Hippert, F., B. Hennion, F.L. Chui, M. Kohgi and T. Satoh, 1988, J. Magn. & Magn. Mater.
76-77, 417.
Holtand-Moritz, E., 1982, in: Valence Instabilities, eds P. Wachter and H. Boppart (North- Holland, Amsterdam) p. 347.
Holland-Moritz, E., 1983, J. Magn. & Magn.
Mater. 38, 253.
100 M. LOEWENHAUPT and K.H. FISCHER Holland-Moritz, E., 1985, J. Magn. & Magn.
Mater. 46-47, 127.
Holland-Moritz, E., and M. Kasaya, 1986, Phys- ica B 136, 424.
Holland-Moritz, E., and M. Loewenhaupt, 1979, J. Phys. Colloq. (Paris) 40, C5-359.
Holland-Moritz, E., and A. Severing, 1986, Z.
Phys. B 63, 313.
Holland-Moritz, E., M. Loewenhaupt, W.
Schmatz and D. Wohlleben, 1977, Phys. Rev.
Lett. 38, 983.
Holland-Moritz, E., D. Wohlleben and M.
Loewenhaupt, 1978, J. Phys. Colloq. (Paris) 39, C6-835.
Holland-Moritz, E., D. Wohlleben and M.
Loewenhaupt, 1982, Phys. Rev. B 25, 7482.
Holland-Moritz, E., E. Braun, B. Roden, P. Per- scheid, E.V. Sampathkumaran and W. Langl, 1987, Phys. Rev. B 35, 3122.
Holland-Moritz, E., E. ZirngiebI and S. Blumen- r6der, 1988, Z. Phys. B 70, 395.
Holland-Moritz, E., W. Weber, A. Severing, E.
Zirngiebl, H. Spille, W. Baus, S. Horn, A.P.
Murani and J.L. Ragazzoni, 1989a, Phys. Rev.
B 39, 6409.
Holland-Moritz, E., W. Weber, G. Michels, W.
Schlabitz, A. Mewis, C. Sauer and H. Mutka, 1989b, Z. Phys. B 77, 105.
Holtzberg, F., J. Flouquet, P. Haen, F. Lapierre, Y. Lassailly and C. Vettier, 1985, J. Appl. Phys.
57, 3152.
Horn, S., E. Holland-Moritz, M. Loewenhaupt, F. Steglich, H. Scheuer, A. Benoit and J. Flouquet, 1981a, Phys. Rev. B 23, 3171.
Horn, S., F. Steglich, M. Loewenhaupt and E.
Holland-Moritz, 198lb, Physica B 107, 103.
Horn, S., F. Steglich, M. Loewenhaupt, H.
Scheuer, W. Felsch and K. Winzer, 1981c, Z.
Phys. B 42, 125.
Houghton, A., N. Read and H. Won, 1987, Phys.
Rev. B 35, 5123.
Houghton, A., N. Read and H. Won, 1988, Phys.
Rev. B 37, 3782.
Ihrig, H., and S. Methfessel, 1976, Z. Phys. B 24, 381.
Irkhin, V.Yu., and M.I. Katsnelson, 1989, Z. Phys.
B 75, 67.
Jaccard, D., R. Cibin, A. Bezinge, J. Sierro, K.
Matho and J. Flouquet, 1988, J. Magn. &
Magn. Mater. 76-77, 255.
Jacoud, J.L., L.P. Regnault, J. Rossat-Mignod, C.
Vettier, P. Lejay and J. Flouquet, 1989, Physica B 156-157, 818.
Jacoud, J.L., L.P. Regnault, J.M. Mignot,
J. Rossat-Mignod, J. Flouquet and P. Lejay, 1992, J. Magn, & Magn. Mater. 108, 131.
Jefferson, J.M., and K.W.H. Stevens, 1978, J. Phys.: Condens. Matter 11, 3919.
Johansson, B., 1979, Phys. Rev. B 20, 1315.
Johansson, B., and A. Rosengren, 1975, Phys. Rev.
B 11, 2836.
Johnson, S.M., J.A.C. Bland, P.J. Brown, A.
Benoit, H. Capellmann, J. Flouquet, H. Spille, F. Steglich and K.R.A. Ziebeck, 1985, Z. Phys.
B 59, 401.
Kaga, H., and T. Yoshida, 1988, Phys. Rev. B 38, 12047.
Kaga, H., and T. Yoshida, 1989, Physica C 159, 727.
Kaga, H., H. Kubo and T. Fujiwara, 1988, Phys.
Rev. B 37, 341.
Kappler, J.P., and A. Meyer, I979, J. Phys. F 9, 143.
Kawakami, N., and A. Okiji, 1985, J. Magn. &
Magn. Mater. 52, 220.
Keiter, H., and G. Czycholl, 1983, J. Magn. &
Magn. Mater. 31,477.
Keiter, H., and J.C. Kimball, 1971, Int. J. Magn.
1, 233.
Kirsch, T., A. Eichler, P. Morin and U. Welp, 1992, Z. Phys, B 86, 83.
Kittel, C., 1963, in: Quantum Theory of Solids (Wiley, New York) ch. 18, p. 360.
Knopp, G., H. Spille, A. Loidl, K. Knorr, U.
Rauchschwalbe, P. Felten, G. Weber, F. Steg- lich and A.P. Murani, 1987, J. Magn. & Magn.
Mater. 63-64, 88.
Knopp, G., A. Loidl, R. Caspary, U. Gottwick, C.D. Bredl, H. Spille, F. Steglich and A.P. Mur- ani, 1988a, J. Magn. & Magn. Mater. 74, 341.
Knopp, G., A. Loidl, K. Knorr, H. Spille, F. Steg- lich and A.P. Murani, 1988b, J. Magn. & Magn.
Mater. 76-77, 420.
Knopp, G., A. Loidl, K. Knott, L. Pawlak, M.
Duczmal, R. Caspary, U. Cottwick, H. Spille, F. Steglich and A.P. Murani, 1989, Z. Phys. B 77, 95.
Kohgi, M., F. Hippert, L.-P. Regnault, J. Rossat- Mignod, B. Hennion, T. Satoh, F.L. Chui, T.
Miura and H. Takei, 1987, Jpn. J. Appl. Phys.
26, 559.
Kohgi, M., M. Ito, T. Satoh, H. Asano, T. Ishigaki and F. Izumi, 1990a, J. Magn. & Magn. Mater.
90-91, 433.
Kohgi, M., T. Satoh, K. Ohoyama, M. Ari and R. Osborn, 1990b, Physiea B 163, 137.
Kohgi, M., K. Ohoyama, A. Oyamada, T. Suzuki and M. Arai, 1990c, Physica B 163, 625.
VF AND HF 4t SYSTEMS 101 Kohgi, M., T. Satoh, K. Ohoyama and M. Arai,
199t, Physica B 169, 501.
Kojima, H., Y. Kuramoto and M. Tachiki, 1984, Z. Phys. B 54, 293.
Kojima, K., H. Hayashi, A. Minami, Y. Kasa- matsu and T. Hihara, 1989, J. Magn. & Magn.
Mater. 81, 267.
Komatsubara, T., N. Sato, S. Kunii, I. Oguro, Y.
Furukawa, Y. Onuki and T. Kasuya, 1983, J. Magn. & Magn. Mater. 31-34, 368.
Koskenmaki, D.C., and K.A. Gschneidner Jr, 1978, in: Handbook on the Physics and Chem- istry of Rare Earths, Vol. 1, eds K.A.
Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 337.
Krill, G., J.P. Kappler, M.F. Ravet, A. Amamou and A. Meyer, 1980, J. Phys. F 10, 1031.
Kunii, S., 1988, J. Magn. & Magn. Mater. 76-77, 337.
Kuramoto, Y., 1983, Z. Phys. B 53, 37.
Kuramoto, Y., 1987, Solid State Commun. 63, 467.
Kuramoto, Y., and H. Kojima, 1985, J. Magn. &
Magn. Mater. 47-48, 329.
Kuramoto, Y., and E. Mfiller-Hartmann, 1985, J. Magn. & Magn. Mater. 52, 122.
Lahiouel, R., R.M. Galera, J. Pierre, E. Siaud and A.P. Murani, 1987, J. Magn. & Magn. Mater.
63-64, 98.
Langreth, D.C., I966, Phys. Rev. 150, 712.
Larson, A.C., and D.T. Cromer, 1961, Acta Crys- tallogr. 14, 73.
Lassailly, Y., C. Vettier, F. Holtzberg, J. Flouquet, C.M.E. Zeyen and F. Lapierre, 1983, Phys. Rev.
B 28, 2880.
Lassailly, Y., S.K. Burke and J. Flouquet, 1985, J. Phys. C 18, 5737.
Lawrence, J.M., 1979, Phys. Rev. B 20, 3770.
Lawrence, J.M., and S.M. Shapiro, 1980, Phys.
Rev. B 22, 4379.
Lawrence, J.M., P.S. Riseborough and R.D.
Parks, 1981, Rep. Progr. Phys. 44, 1.
Lebech, B., Z. Smetana and V. Sima, 1987, J.
Magn. & Magn. Mater. 70, 97.
Lee, P.A., T.M. Rice, J.W. Serene, L.J, Sham and J.W. Witkins, 1986, Comments Condens.
Mater. Phys. 12, 99.
Lin, C.L., J. Teter, J.E. Crow, T. Mihalisin, J. Brooks, A.I. Abou-Aly and G.R. Stewart, 1985, Phys. Rev. Lett. 54, 2541.
Lin, C.L., A. Wallash, J.E. Crow, T. Mihalisin and P. Schlottmann, 1987, Phys. Rev. Lett. 58, 1232.
Liu, S.H., 1989, Phys. Rev. B 39, 1403.
Loewenhaupt, M., 1984a, in: Moment Formation
in Solids, ed. W.J.L. Buyers (Plenum, New York) p. 215.
Loewenhaupt, M., 1984b, unpublished data.
Loewenhaupt, M., and H. Bjerrum-MOller, 1981, Physica B 108, 1349.
Loewenhaupt, M., and E. Holland-Moritz, 1979a, J. Magn. & Magn. Mater. 14, 227.
Loewenhaupt, M., and E. Holland-Moritz, 1979b, J. Appl. Phys. 50, 7456.
Loewenhaupt, M., and M. Prager, 1986, Z. Phys.
B 62, 195.
Loewenhaupt, M., and F. Steglich, 1977, in: Crys- tal Field Effects in Metals and Alloys, ed. A.
Furrer (Plenum, New York) p. 198.
Loewenhaupt, M., B.D. Rainford and F. Steglich, 1979, Phys. Rev. Lett. 72, 1709.
Loewenhaupt, M., S. Horn and F. Steglich, 1981, Solid State Commun. 39, 295.
Loewenhaupt, M., J.M. Carpenter and C.-K.
Loong, 1985, J. Magn. & Magn. Mater. 52, 245.
Loewenhaupt, M., W. Reichardt, R. Pynn and E.
Lindley, 1987, J. Magn. & Magn. Mater. 63-64, 73.
Loewenhaupt, M., M. Prager, E. Gratz and B.
Frick, 1988, J. Magn. & Magn. Mater. 76-77, 415.
Loewenhaupt, M., E. Gratz, N. Pillmayr and H.
Mfiller, 1990, Physica B 163, 427.
Loidl, A., G. Knopp, H. Spille, F. Steglich and A.P. Murani, 1989, Physica B 156-157, 794.
Loong, C.-K., B.H. Grier, S.M. Shapiro, J.M.
Lawrence, R.D. Parks and S.K. Sinha, 1987, Phys. Rev. B 35, 3092.
Loong, C,-K., J. Zarestky, C. Stassis, O.D.
McMasters and R.M. Nicklow, 1988, Phys.
Rev. B 38, 7365.
Lysak, M.J., and D.E. MacLaughlin, 1985, Phys.
Rev. B 31, 6963.
MacLaughlin, D.E., F.R. dc Boer, J. Bijvoet, P.F.
de Chatel and W.C.M. Mattens, 1979, J. Appl.
Phys. 50, 2094.
Maekawa, S., S. Takahashi, S. Kashiba and M.
Tachiki, 1985a, J. Appl. Phys. 57, 3169.
Maekawa, S., S. Takahashi, S. Kashiba and M.
Tachiki, 1985b, J. Phys. Soc. Jpn. 54, 1955.
Maekawa, S., S. Takahashi, S. Kashiba and M.
Tachiki, 1985c, J. Magn. & Magn. Mater. 52, 149.
Martens, W.C.M., F.R. de Boer, A.P. Murani and G.H. Lander, 1980, J. Magn. & Magn. Mater.
15-18, 973.
Mazzaferro, J., C.A. Balseiro and B. Alascio, 1981, Phys. Rev. Lett. 47, 274.
McWhan, D.B., S.M. Shapiro, J. Eckert, H.A.
102 M. LOEWENHAUPT and K.H. FISCHER Mook and R.J. Birgeneau, 1978, Phys. Rev. B
18, 3623.
Mignot, J.-M., J.L. Jacoud, L.P. Regnault, J. Rossat-Mignod, P. Haen, P. Lejay, Ph. Bout- rouille, B. Hennion and D. Pettigrand, 1990, Physica B 163, 611.
Mignot, J.-M., Ph. Boutrouille, L.P. Regnault, P.
Haen and P. Lejay, 1991, Solid State Commun.
77, 317.
Millis, A.J., and P.A. Lee, 1987, Phys. Rev. B 35, 3394.
Mishchenko, A.S., and K.A. Kikoin, 1991, J. Phys.: Condens. Matter 3, 5937.
Mook, H.A., and F. Holtzberg, 1981, in: Valence Fluctuations in Solids, eds L. M. Falicov, W.
Hanke and M. B. Maple (North-Holland, Amsterdam) p. 1 ! 3.
Mook, H.A., and R.M. Nicklow, 1979, Phys. Rev.
B 20, 1656.
Mook, H.A., T. Penny, F. Holtzberg and M.W.
Shafcr, 1978a, J. Phys. Colloq. (Paris) 39, C6- 837.
Mook, H.A., R.M. Nicklow, T. Penny, F. Holtz- berg and M.W. Shafer, 1978b, Phys. Rev. B 18, 2925.
Mook, H.A., D.B. McWhan and F. Holtzberg, 1982, Phys. Rev. B 25, 4321.
Moon, R.M., and W.C. Koehler, 1979, J. Appl.
Phys. 50, 2089.
Moon, R.M., W.C. Koehler, D.B. McWhan and F. Holtzberg, 1978, J. Appl. Phys. 49, 2107.
Moon, R.M., S.H. Liu and K. Werner, 1983, J.
Magn. & Magn. Mater. 31-34, 387.
Morin, P., 1988, J. Magn. & Magn. Mater. 71, 151.
Morin, P., C. Vettier, J. Flouquet, M. Konczy- kowski, Y. Lassailly, J.M. Mignot and U. Welp,
1988, J. Low Temp. Phys. 70, 377.
Moshchalkov, V.V., and N.B. Brandt, 1986, Soy.
Phys. Usp. 29, 725.
Mfiller Hartmann, E., 1984, Z. Phys. B 57, 281.
Murani, A.P., 1983a, J. Phys. F 16(33), 6359.
Murani, A.P., 1983b, Phys. Rev. B 28, 2308.
Murani, A.P., 1985a, Phys. Rev. Lett. 54, 1444.
Murani, A.P., 1985b, J. Magn. & Magn. Mater.
47-48, 142.
Murani, A.P., 1986, J. Magn. & Magn. Mater. 61, 212.
Murani, A.P., 1987a, Phys. Rev. B 36, 5705.
Murani, A.P., 1987b, in: Theoretical and Experi- mental Aspects of Valence Fluctuations and Heavy Fermions, eds L.C. Gupta and S.K.
Malik (Plenum, New York) p. 287.
Murani, A.P., K. Knorr and K.H.J. Buschow,
1977, in: Crystal Field Effects in Metals and Alloys, ed. A. Furrer (Plenum, New York) p.
268.
Murani, A.P., K. Knorr, K.HJ. Buschow, A.
Benoit and J. Flouquet, 1980, Solid State Corn- mun. 36, 523.
Murani, A.P., W.C.M. Mattens, F.R. de Boer and G.H. Lander, 1985, Phys. Rev. B 31, 52.
Murani, A.P., R. Currat, A. Severing and R.
Raphel, 1990a, Physica B 163, 717.
Murani, A.P., W.G. Marshall, A.D. Taylor and R. Osborn, 1990b, ISIS experimental report ULS 85/1, p. A164.
Neuhaus, W., 1987, Berichte der KFA Jfilich, Jill- 2165.
Newns, D.M., and N. Read, 1987, Adv. Phys. 36, 799.
Nozi6res, P., 1974, J. Low Temp. Phys. 17, 31.
Nunez, V., R. Trump, P.J. Brown, T. Chattopad- hyay, M. Loewenhaupt and F. Tasset, 1992, J. Phys.: Condens. Matter 4, l 115.
Ohkawa, F.J., and T. Yamamoto, 1987, Physica B 148, 84.
Ohoyama, K., M. Kohgi, T. Nakane, M. Arai, A.D. Taylor, A. Oyamada and T. Suzuki, 1992, Physica B 180 + 181,250.
Onuki, Y., and T. Komatsubara, 1987, J. Magn.
& Magn. Mater. 63-64, 281.
Onuki, Y., Y. Shimizu, M. Nishihara, Y. Machii and T. Komatsubara, 1985a, J. Phys. Soc. Jpn.
54, 1964.
Onuki, Y., Y. Machii, Y. Shimizu, T. Komatsu- bara and T. Fujita, 1985b, J. Phys. Soc. Jpn.
54, 3562.
Orlov, V.G., 1988, Solid State Commun. 67, 689.
Osborn, R., and E.A. Goremychkin, 1991, ISIS report 1991, Vol. II, p. A208.
Osborn, R., M. Loewenhaupt, B.D. Rainford and W.G. Stirling, 1987, J. Magn. & Magn. Mater.
63-64, 70.
Osborn, R., K.A. McEwen, E.A. Goremychkin and A.D. Taylor, 1990, Physiea B 163, 37.
Osborn, R., S.W. Lovesey, A.D. Taylor and E.
Balcar, 1991, in: Handbook on the Physics and Chemistry of Rare Earths, Vol. 14, eds K.A.
Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 1.
Ott, H.R., 1987, in: Progress in Low Temperature Physics, Vol. XI, ed. D.F. Brewer (Elsevier, Amsterdam) p. 215.
Ott, H.R., H. Rudiger and F. Hulliger, 1985, Solid State Commun. 55, 113.
Panissod, P., M. Benakki and A. Qachaou, 1988, J. Phys. Colloq. (Paris) 49, C8-685.
VF AND HF 4f SYSTEMS 103 Panousis, N.T., and K.A. Gschneidner Jr, 1972,
Phys. Rev. B 5, 4767.
Perez, I., G. Liang, J.B. Zhou, H. Jhans, S.A.
Shaheen and M. Croft, 1990, Physcia B 163, 618.
Perscheid, B., E.V. Sampathkumaran and G.
Kaindl, 1985, J. Magn. & Magn. Mater. 47 + 48, 410.
Peysson, Y., C. Ayache, J. Rossat-Mignod, S.
Kanii and T. Kasuya, 1986, J. Phys. (Paris) 47, 113.
Pintschovius, L., E. Holland-Moritz, D.
Wohlleben, S. St6hr and J. Liebertz, 1980, Solid State Commun. 34, 953.
Pintschovius, L., E. Holland Moritz, D.
Wohlleben, S. St6hr, J. Liebertz, W. Assmus, C.
Stassis, C.-K. Loong, J. Zarestky and R.M.
Moon, 1983, Solid State Commun. 47, 663.
Polatsek, G., and P. Bonville, 1992, Z. Phys. B 88, 189.
Rainford, B.D., B. Buras and B. Lebech, 1977, Physica B 86-88, 41.
Rajan, V.T., 1983, Phys. Rev. Lett. 51, 308.
Rasul, J.W., and P. Schlottmann, 1989a, Phys.
Rev. B 39, 3065.
Rasul, J.W., and P. Schlottmann, 1989b, Phys.
Rev. Lett. 62, 1325.
Read, N., D.M. Newns and S. Doniach, 1984, Phys. Rev. B 30, 3841.
Regnault, L.P., W.A.C. Erkelens, J. Rossat- Mignod, C. Vettier, S. Kunii and T. Kasuya, 1988, J. Magn. & Magn. Mater. 76-77, 413.
Regnault, L.P., J.L. Jacoud, J.M. Mignot, J. Rossat-Mignod, C. Yettier, P. Lejay and J. Flouquet, 1990, Physica B 163, 606.
Reichardt, W., and N. Nficker, 1984, J. Phys. F 14, L135.
Renker, B., E. Gering, F. Gompf, H. Schmidt and H. Rietschel, 1987, J. Magn. & Magn. Mater.
63 + 64, 31.
Ribault, M., J. Flouquet, P. Haen, F. Lapierre, J.M. Mignot and F. Holtzberg, 1980, Phys. Rev.
Lett. 45, I295.
Robinson, J.M., 1979, Phys. Rev. Rep. 51, 1.
Rogl, P., 1984, in: Handbook on the Physics and Chemistry of Rare Earths, Vol. 7, eds K.A.
Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 1.
R6hler, J., 1987, in: Handbook on the Physics and Chemistry of Rare Earths, Vol. 10, eds K.A.
Gschneidner Jr and L. Eyring (North-Holland, Amsterdam) p. 453.
Rossat-Mignod, J., L.P. Regnault, J.L. Jacoud, C. Vettier, P. Lejay, J. Flouquet, E. Walker, D.
Jaccard and A. Amato, 1988, J. Magn. & Magn.
Mater. 76-77, 376.
Rossel, C., K.N. Yang, M.B. Maple, Z. Fisk, E.
Zirngiebl and J.D. Thompson, 1987, Phys. Rev.
B 35, 1914.
Sales, B.C., and R. Viswanathan, t976, J. Low Temp. Phys. 23, 449.
Schefzyk, R., W. Lieke, F. Steglich, T. Goto and B. L6thi, 1984, J. Magn. & Magn. Mater. 45, 229.
Schlottmann, P., 1982, Phys. Rev. B 25, 2371.
Schlottmann, P., 1984, Phys. Rev. B 29, 4468.
Schlottmann, P., 1989, Phys. Rep. 181, 1.
Schmidt, H.J., and E. Mfiller-Hartmann, 1989, Z.
Phys. B 75, 331.
Schmitt, D., P. Morin and J. Pierre, 1978, J. Magn. & Magn. Mater. 8, 249.
Schr6der, A., H.G. Schlager and H. v. L6hneysen, 1992, J. Magn. & Magn. Mater. 108, 47.
Severing, A., and A.P. Murani, 1990, Physica B 163, 699.
Severing, A., W. Reichardt, E. Holland Moritz, D. Wohlleben and W. Assmus, 1988, Phys. Rev.
B 38, 1773.
Severing, A., E. Holland Moritz, B.D. Rainford, S.R. Culverhouse and B. Frick, 1989a, Phys.
Rev. B 39, 2557.
Severing, A., E. Holland-Moritz and B. Frick, 1989b, Phys. Rev. B 39, 4164.
Severing, A., A.P. Murani, J.D. Thompson, Z.
Fisk and C.-K. Loong, 1990a, Phys. Rev. B 41, 1739.
Severing, A., E. Gratz, B.D. Rainford and K. Yos- himura, 1990b, Physica B 163, 409.
Shapiro, S.M., 1986, Physica B 136, 365.
Shapiro, S.M., and B.H. Grier, 1982, Phys. Rev.
B 25, 1457.
Shapiro, S.M., R.J. Birgeneau and E. Bucher, 1975, Phys. Rev. Lett. 34, 470.
Shapiro, S.M., J.D. Axe, R.J. Birgeneau, J.M.
Lawrence and R.D. Parks, 1977, Phys. Rev. B 16, 2225.
Shapiro, S.M., H. Bjerrum-MOller, J.D. Axe, R.J. Birgeneau and E. Bucher, 1978, J. Appl.
Phys. 49, 2101.
Shapiro, S.M., E. Gurewitz, R.D. Parks and L.D.
Kupferberg, 1979, Phys. Rev. Lett. 43, 1748.
Shapiro, S.M., C. Stassis and G. Aeppli, 1989, Phys. Rev. Lett. 62, 94.
Shiba, H., 1975, Prog. Theor. Phys. 54, 967.
Shimizu, T., H. Yasuoka, Z. Fisk and J.L. Smith, 1987, J. Phys. Soc. Jpn. 56, 4113.
Smith, H.G., G. Dolling and T. Goto, 1985, Solid State Commun. 53, t5.