Rikio Konno
Kindai University Technical College, Japan
Title: Theory of thermal expansion of magnetic superconductors
Biography
Biography: Rikio Konno
Abstract
We investigated thermal expansion of ferromagnetic superconductors below the superconducting transition temperature and that of antiferromagnetic superconductors below the Neel temperature within the mean-field approximation. Both of them were based on the free energy derived from microscopic single band models. Takahashi’s method was applied to the free energy in order to obtain thermal expansion. In the ferromagnetic superconductors, the superconducting gap of the A2 phase in liquid 3He and that of the line node were used. We found that an anomaly of the thermal expansion exists in the vicinity of the superconducting transition temperature. In the antiferromagnetic superconductors, the isotropic singlet superconducting gap was used. We found that the jump of thermal expansion appears at the superconducting transition temperature. The thermal expansion has an exponential behavior at very low temperatures. The thermodynamic Gruneisen’s relation is automatically satisfied in both the cases.