Strong correlation between ferromagnetic superconductivity and pressure-enhanced ferromagnetic fluctuations in UGe${}_2$

Abstract

We have measured magnetization at high pressure in the uranium ferromagnetic superconductor UGe${}_2$ and analyzed the magnetic data using Takahashi's spin fluctuation theory. There is a peak in the pressure dependence of the width of the spin fluctuation spectrum in the energy space $T_0$ at $P_x$, the phase boundary of FM1 and FM2 where the superconducting transition temperature $T_{sc}$ is highest. This suggests a clear correlation between the superconductivity and pressure-enhanced magnetic fluctuations developed at $P_x$. The pressure effect on $T_{Curie}/T_0$, where $T_{Curie}$ is the Curie temperature, suggests that the less itinerant ferromagnetic state FM2 is changed to a more itinerant one FM1 across $P_x$. Peculiar features in relations between $T_0$ and $T_{sc}$ in uranium ferromagnetic superconductors UGe${}_2$, URhGe and UCoGe are discussed in comparison with those in high-$T_c$ cuprate and heavy fermion superconductors.

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Cited by in corpus (3)

• Coexistence of ferromagnetic fluctuations and superconductivity in the actinide superconductor UTe2
• Novel critical behavior of magnetization in URhSi:Similarities to uranium ferromagnetic superconductors UGe${}_2$ and URhGe
• Metamagnetic phase transition in ferromagnetic superconductor URhGe