The possibility of a coexistent superconducting and magnetic phase in layered transition metal dichalcogenides of the type MX 2 A x is investigated (M =transition metal; X = S, Se; A = magnetic ion; x ≥ 0.25). Describing such systems with a model in which a highly anisotropic electron gas interacts with a quasi-two-dimensional Heisenberg magnet, we find the following conditions for coexistence: (1) The coupling between adjacent layers of ferromagnetically ordered magnetic ions needs to be antiferromagnetic (〈S z〉 = 0) in order to have no pair-breaking internal fields. (2) The exchange interaction between conduction electrons and magnetic ions must be very small (≲ 0.003 eV), since otherwise, due to the high concentration of localized magnetic moments, spin-flip scattering processes and spin fluctuations would destroy superconductivity. The theoretical prediction for the persistence of superconductivity up to concentrations of x≈ 0.25 of magnetic ions is compared with recent experiments on Eu-intercalated TaS 2 and NbS 2 and related compounds showing a tendency for ferromagnetically ordered layers of Eu impurities and antiferromagnetic coupling between neighboring layers but no superconductivity for x exceeding a few percent. Reasons for the quick disappearance of superconductivity in these systems and criteria for possible observation of “high-magnetic-impurity-concentration superconductivity” in other layered compounds are given.
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References
G. V. S. Rao, M. W. Shafer, and L. J. Tao, Mat. Res. Bull. 8, 1231 (1973).
M. W. Shafer, G. V. S. Rao, and L. J. Tao, in Proc. Int. Conf. Magnetism, ICM-73 (Moscow, 1974), Vol. II, p. 283.
T. Sambongi, J. Low Temp. Phys. 18, 139 (1975).
J. C. Tsang, M. W. Shafer, and B. L. Crowder, Phys. Rev. B 11, 155 (1975).
J. M. Chen and C. S. Wang, Bull. Amer. Phys. Soc. 19, 485 (1974).
R. C. Morris and R. V. Coleman, Phys. Rev. B 7, 991 (1973).
R. A. Klemm, M. R. Beasley, and A. Luther, J. Low Temp. Phys. 16, 607 (1974).
K. Aoi, W. Dieterich, and P. Fulde, Z. Physik 267, 223 (1974).
J. M. Voorhoeve-van den Berg and R. C. Sherwood, J. Phys. Chem. Solids 32, 167 (1971).
J. J. Hauser, M. Robbins, and F. J. DiSalvo, Phys. Rev. B 8, 1038 (1973).
J. M. Voorhoeve-van den Berg and M. Robbins, J. Solid State Chem. 1, 134 (1970).
L. F. Mattheis, Phys. Rev. B 8, 3719 (1973).
C. Y. Fong and M. L. Cohen, Phys. Rev. Lett. 32, 720 (1974).
W. E. Lawrence and S. Doniach, in Proc. Twelfth Int. Conf. Low Temp. Phys., E. Kanda, ed. (Academic Press of Japan, Kyoto, 1971), p. 361.
T. Tsuzuki, J. Low Temp. Phys. 9, 525 (1972).
U. Ambegaokar and A. Griffin, Phys. Rev. 137A, 1151 (1965).
K. Maki, in Superconductivity, Vol. 2, R. D. Parks, ed. (Marcel Dekker, New York, 1969), p. 1035.
J. Keller and R. Benda, J. Low Temp. Phys. 2, 141 (1970).
T. Kusakabe, Progr. Theor. Phys. 43, 907 (1970).
V. A. Moskalenko and L. Z. Kon, Sov. Phys. JETP 23, 479 (1966).
P. Will and M. Brusberg, J. Low Temp. Phys. 18, 169 (1975).
P. Entel and W. Klose, Z. Physik B 21, 363 (1975).
P. Fulde and K. Maki, Phys. Rev. 141, 275 (1966).
S. V. Tyablikov, Ukrain. Math. Zh. 11, 287 (1959).
W. Marshall and R. D. Lowde, Rep. Progr. Phys. 31, 705 (1968).
D. Furmann and M. Blume, Phys. Rev. B 10, 2068 (1974).
P. Entel and W. Klose, J. Low Temp. Phys. 17, 529 (1974).
E. A. Antonova, S. A. Medvedev, and I. Yu. Shebalin, Sov. Phys. JETP 30, 181 (1970).
E. I. Katz, Sov. Phys. JETP 31, 707 (1970).
J. M. Voorhoeve-van den Berg, J. Less-Common Metals 26, 399 (1972).
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Entel, P., Crisan, M., Bongi, G. et al. Possible coexistence of superconductivity and magnetism in layered compounds. J Low Temp Phys 23, 157–176 (1976). https://doi.org/10.1007/BF00117249
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DOI: https://doi.org/10.1007/BF00117249