Resolving and routing magnetic polymorphs in a 2D layered antiferromagnet.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Polymorphism, the existence of multiple crystal or molecular structures, is fundamental across sciences.
• Van der Waals antiferromagnets exhibit a novel magnetic polymorphism with layer-selective magnetic structures and identical total magnetization.
• Resolving and controlling these magnetic polymorphs presents significant scientific challenges.

Purpose of the Study:

• To investigate and demonstrate controllable magnetic polymorphism in 2D layered antiferromagnets.
• To elucidate the mechanisms behind layer-selective magnetic switching.
• To explore the potential applications of magnetic polymorphism in novel electronic devices.

Main Methods:

• Utilized phase-resolved magnetic second harmonic generation microscopy.
• Employed a nonlinear magneto-optical technique to analyze spin-flip transitions.
• Investigated CrSBr bilayers and tetralayers to resolve polymorphic transitions.

Main Results:

• Successfully demonstrated deterministic and layer-selective switching of magnetic polymorphs in CrSBr.
• Unambiguously resolved polymorphic spin-flip transitions by analyzing both amplitude and phase of light.
• Identified a 'layer-sharing' effect, where extended layers act as control bits for transition routing.

Conclusions:

• Controllable magnetic polymorphism is achievable in 2D van der Waals antiferromagnets.
• The 'layer-sharing' effect provides a mechanism for deterministic control of magnetic states.
• This controllable polymorphism offers new avenues for designing spintronic and opto-spintronic devices for probabilistic computation and neuromorphic engineering.