Emergent Ferromagnetic Ladder Excitations in Heavy Fermion Superconductor CeSb_{2}.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Magnetism

Background:

• Low-dimensional spin fluctuations are critical in unconventional superconductors.
• Quasi-one-dimensional spin excitations may indicate spin-triplet superconductivity.
• The heavy fermion superconductor CeSb2 shows an unusual upper critical field, hinting at triplet pairing.

Purpose of the Study:

• Investigate the nature of spin excitations in CeSb2.
• Determine the relationship between magnetic excitations and superconductivity in CeSb2.
• Explore the role of low-dimensional magnetism in unconventional superconductivity.

Main Methods:

• Inelastic neutron scattering was employed to probe magnetic excitations.
• Analysis involved fitting data to a ferromagnetic spin ladder model.
• Magnetic structure and dynamics were characterized.

Main Results:

• Quasi-one-dimensional magnetic excitations were discovered in CeSb2.
• The excitations originate from nearly square Ce layers with orthorhombic deformation.
• A ferromagnetic spin ladder model accurately describes the observed magnetic excitations.
• Diffuse magnetic excitations persist above the Néel temperature (T_N).

Conclusions:

• Quasi-one-dimensional spin fluctuations are present in CeSb2.
• These fluctuations, described by a spin ladder model, are linked to the material's structure.
• Ferromagnetic paramagnons likely contribute to the pressure-induced superconductivity by influencing magnetic order suppression.