During the last few years superconductive systems of heavy fermions with highly large values ofm* and electronic heat capacityγT have been thoroughly investigated.

The following compounds viz CeCu₂Si₂ (T_c=0.6 K;γ=1100*), UBe₁₃(T_c=0.95 K;γ=1000) and UPt₃ (T_c=0.5 K;γ=450)(I) may be referred to such systems as well as the U and Ce compounds: U₂Pt C₂ (T_c=1.47 K;γ=75), U₆Fe (T_c=3.86 K;γ=25), U₆Co (T_c=2.3 K;γ=21), URu₂Si₂ (T_c=0.68 K,γ=17.6), as well asα-U (T_c=2.1;γ=12), CeRu₃Si₂ (T_c=1 K;γ=39), CeOs₂ (T_c=1,1 K;γ=22), CeRu₂ (T_c=6 K;γ=23.3) and α-Ce (T_c≲2K;γ=14) (Alekseevskii and Homskiy 1985).

It should be noted that there exists a class of U and Ce compounds with a similar structure as those given above, which undergo transition to superconductive state, but are not characterized by abnormal values ofm* (Alekseevskii 1984).

Many authors considered superconductivity of heavy fermion systems as unusually anisotropic where charge carrier coupling occurs in P-state (Stewart 1984). On the other hand such a view does not agree with many experimental results, e.g. lack of anisotropy Hc₂ for UBe₁₃ (Alekseevskiiet al 1985) as predicted by Gorkov (1984) and the results of investigation of the Josephson effect. The Hall-effect investigations for UBe₁₃ in a wide range of fields and temperatures (Alekseevskii 1984) make it possible to consider systems with two types of carriers—heavy and light. The unique properties of the above systems in a number of cases are possibly caused by these two types of carriers and the peculiarity of interaction between them.