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Superconductivity induced by longitudinal ferromagnetic fluctuations in UCoGe.
1Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan. t.hattori@scphys.kyoto-u.ac.jp
Physical Review Letters
|March 10, 2012
Summary
Superconductivity in UCoGe is linked to ferromagnetic spin fluctuations. Magnetic fields tune these fluctuations, revealing a unique spin-triplet superconductivity mechanism.
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- Ferromagnetic (FM) superconductors exhibit complex interplay between magnetic order and superconductivity.
- UCoGe is a material where superconductivity (T(SC) ~ 0.6 K) and ferromagnetism (T(Curie) ~ 2.5 K) coexist.
Purpose of the Study:
- To investigate the relationship between longitudinal FM spin fluctuations and superconductivity in UCoGe.
- To elucidate the mechanism behind the unique spin-triplet superconductivity in this material.
Main Methods:
- Angle-resolved Nuclear Magnetic Resonance (NMR) measurements.
- Meissner effect measurements.
- Application of magnetic fields along the c axis (H∥c).
- Theoretical model calculations.
Main Results:
- Superconductivity in UCoGe is strongly coupled with longitudinal FM spin fluctuations along the c axis.
- H∥c suppresses FM fluctuations, and superconductivity is observed only when these fluctuations are active.
- A specific magnetic field region allows for the coexistence of superconductivity and active FM fluctuations.
Conclusions:
- Longitudinal FM spin fluctuations, tuned by H∥c, are crucial for inducing spin-triplet superconductivity in UCoGe.
- This study provides the first clear evidence directly linking FM fluctuations to superconductivity.
- The findings offer insights into unconventional superconductivity mechanisms in magnetic materials.
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