Tunable giant magnetoresistance in a single-molecule junction.

Area of Science:

• Condensed Matter Physics
• Molecular Electronics
• Spintronics

Background:

• Controlling electronic transport in single-molecule junctions is essential for advancing molecular electronics and spintronics.
• The spin degree-of-freedom in magnetic molecular devices offers a pathway to manipulate charge transport.
• Magnetic properties of ion centers critically influence electron transport through molecules.

Purpose of the Study:

• To demonstrate the selection of electron pathways in single-molecule devices by manipulating magnetic fields.
• To investigate the resulting tunable anisotropic magnetoresistance.
• To explore the potential applications in molecular spintronics.

Main Methods:

• Utilizing the Kondo effect to probe tunneling electron pathways, observed as peak or dip line shapes.
• Applying external magnetic fields to induce magnetic reorientation of transition metal centers.
• Analyzing the re-hybridization of molecular orbitals due to magnetic reorientation.

Main Results:

• Achieved tunable anisotropic magnetoresistance up to 93% by selecting between two molecular orbitals.
• Demonstrated that magnetic reorientation of the transition metal center tunes electron pathways.
• Observed remarkably low energy changes (< 1 meV) for spin-reorientations.

Conclusions:

• Electron pathways in single-molecule devices can be controlled via magnetic fields.
• Tunable anisotropic magnetoresistance is a viable mechanism for controlling electronic transport.
• The findings pave the way for novel molecular spintronic devices.