Exchange-induced spin polarization in a single magnetic molecule junction

Area of Science:

• Molecular spintronics
• Quantum magnetism
• Nanoscale electronic devices

Background:

• Spintronic devices require spin-polarized currents, often achieved via exchange-bias in larger magnetic materials.
• Single magnetic molecules offer a potential route to miniaturize spintronic components.

Purpose of the Study:

• To demonstrate observable and usable exchange-split spin states in a single magnetic molecule.
• To explore the use of single molecules in creating spin-polarized currents at zero magnetic field.

Main Methods:

• Fabrication of a molecular junction using a redox-active porphyrin as a transport channel and a dysprosium-based single-molecule magnet within a graphene nano-gap.
• Conducting single-molecule transport measurements in a magnetic field.
• Utilizing milikelvin torque magnetometry and comparing with a diamagnetic isostructural compound.

Main Results:

• Observation of exchange-split spin channels with distinct spin-polarizations in a single magnetic molecule.
• Demonstration that spin-polarization is highly dependent on magnetic field orientation.
• Unraveling the influence of single-molecule anisotropy and molecular orientation on spin states.

Conclusions:

• Exchange-split spin states are achievable and controllable at the single-molecule level.
• This work establishes a foundation for spin-exchange mechanisms in molecular electronics.
• A novel method is presented for quantifying the internal spin structure of single molecules across different oxidation states.