Spin jam induced by quantum fluctuations in a frustrated magnet

Area of Science:

• Condensed Matter Physics
• Magnetism
• Materials Science

Background:

• Traditional spin glass research focuses on randomness and defects.
• Dense frustrated systems were also explained by this defect-driven paradigm.
• Recent theories propose defect-free mechanisms for glassy states, like quantum fluctuations.

Purpose of the Study:

• To experimentally investigate glassy states in defect-free frustrated magnets.
• To identify new mechanisms beyond defects driving magnetic glassiness.
• To characterize a novel glassy state, termed 'spin jam', in a specific material.

Main Methods:

• Studied the effects of nonmagnetic impurity (Ga3+) concentration on SrCr9pGa12-9pO19 (SCGO(p)).
• Investigated a highly frustrated magnet with a quasi-2D triangular system of bipyramids.
• Analyzed magnetic properties across varying impurity levels to identify distinct phases.

Main Results:

• Observed two distinct phases of glassiness in SCGO(p) as impurity concentration changed.
• Identified an exotic glassy state, the 'spin jam', in the high magnetic concentration region (p > 0.8).
• Found a cluster spin glass phase for lower magnetic concentrations (p < 0.8).
• Demonstrated that the 'spin jam' state is insensitive to low concentrations of defects.

Conclusions:

• The 'spin jam' state exists near the clean limit of frustrated magnets and is defect-insensitive.
• This finding challenges the conventional understanding of spin glasses being solely defect-driven.
• The 'spin jam' provides a new perspective for understanding glassy states in dense frustrated magnets.