Field-induced magnetic instability within a superconducting condensate

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Strongly correlated electron materials exhibit complex electronic phases stabilized by external stimuli like magnetic fields.
• Superconducting materials, such as those in the RCoIn5 family, can host competing electronic orders.
• Understanding phase transitions in these materials is crucial for developing novel electronic devices.

Purpose of the Study:

• To investigate the field-induced quantum phase transition in superconducting Neodymium-Cerium Cobalt Iridium 5 (Nd_0.05Ce_0.95CoIn₅).
• To characterize the nature of the antiferromagnetic phases separated by this transition.
• To elucidate the driving mechanism behind the observed magnetic instability.

Main Methods:

• Application of controlled magnetic fields to single-crystal Nd_0.05Ce_0.95CoIn₅ samples.
• Experimental techniques to probe magnetic ordering and electronic properties under varying fields.
• Analysis of the critical field (μ₀H* = 8 T) where the transition occurs.

Main Results:

• A quantum phase transition was identified at μ₀H* = 8 T, separating two antiferromagnetic phases with identical magnetic symmetry.
• At zero field, a spin-density wave (SDW) phase is observed, which is suppressed at the critical field.
• For fields above H*, a new spin-density phase emerges, exhibiting similarities to the Q phase in CeCoIn₅.

Conclusions:

• The magnetic instability is proposed to be driven by modifications to the superconducting condensate at the critical field, rather than being purely magnetically driven.
• This finding highlights the intricate interplay between superconductivity and magnetism in strongly correlated systems.
• The study provides new insights into the mechanisms governing quantum phase transitions in novel materials.