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Volume 6

Research & Reviews: Journal of Material Sciences

ISSN: 2321-6212

Magnetic Materials 2018

October 22-23, 2018

October 22-23, 2018 | Rome, Italy

International Conference on

Magnetism and Magnetic Materials

Res. Rev. J Mat. Sci. 2018, Volume 6

DOI: 10.4172/2321-6212-C6-030

Magnetic fluctuations in unconventional superconductors: The onset of superconducting phase

transition

Sung-Ho Salk

1, 2

Korea Academy of Science and Technology, South Korea

Pohang University of Science and Technology, South Korea

e explore how antiferromagnetic spin fluctuations lead to the onset of unconventional superconducting phase transition

in the Cu-based, Fe-based and heavy fermion superconductors. Realizing that electron has both the spin and the

charge degrees of freedom, we will pay special attention to both the spin and the charge dynamics in line with the magnetic

spin susceptibility and the optical conductivity respectively. This study helps us understand how common features (universal

scaling behaviors) are revealed in the measurements of the unconventional superconductors. In this regard we first examine the

observed phase diagrams of the Cu-based superconductors in light of interplay between the two degrees of freedom, based on

our earlier proposed gauge theoretic approach (Ref. 1) to the slave-boson represented t-J Hamiltonian. This theory consistently

provided qualitative agreements with all other measurements including optical conductivity and neutron scattering. We discuss

that the onset of superconductivity is caused by the coupling of the spin (spinon) pairing order with the charge (holon) pairing

order, thus revealing the interplay between the spin and the charge degrees of freedom. Further we explain the universal scaling

behaviors of the linear increase of magnetic spin resonance peak energy with the antiferromagnetic coupling energy J and that

of the mid-infrared peak location energy with J, for both of which the interplay of the two degrees of freedom is found to play

a major role.