Introduction of Uranium-Based Heavy Fermion Superconductors

1 Introduction of Uranium-Based Heavy Fermion Superconductors 

The first heavy fermion superconductor was discovered in CeCu2Si2 [19]. Common properties in a heavy fermion superconductor are large electronic specific heat coefficient, suggesting that the effective masses of the conduction electrons are 100 times higher than the static mass of an electron, and the unconventional superconductivity is difficult to explain by the BCS theory. It has been believed that the enhancement of the effective masses of conduction electrons in 

7 STUDY OF EXOTIC URANIUM COMPOUNDS USING U MOSSBAUER SPECTROSCOPY 

TABLE 7.2 Characteristic Physical Properties in Uranium-Based Superconductors, UPd2Al3. URu2Si2, and UPt3 [20,22-24]  

Characteristic temperatures associated with heavy fermion behaviors were investigated by both macroscopic and microscopic measurements. On the viewpoint of the magnetic properties, the temperature dependence of the magnetic susceptibility suggests the presence of the characteristic temperature for heavy fermion behaviors. This is a maximum of the magnetic susceptibility at a certain temperature, called [20,22,30]. It has been believed that this behavior is correlated 

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