Observation of Two-Terminal CISS Magnetoresistance with Nonmagnetic Contacts

Area of Science:

• Condensed matter physics
• Spintronics
• Materials science

Background:

• Chirality-dependent asymmetric magnetoresistance (MR) in ferromagnet (FM)/nonmagnet (NM) systems is often attributed to the chirality induced spin selectivity (CISS) effect.
• The CISS effect assumes chiral media generate spin-polarized currents detected by ferromagnetic electrodes.

Purpose of the Study:

• To investigate the generality of the two-terminal asymmetric MR response.
• To demonstrate that chirality-dependent MR can manifest even with non-spin-detecting electrodes.
• To differentiate the observed MR from electromagnetochiral anisotropy (EMChA).

Main Methods:

• Contacting achiral media with nonmagnetic electrodes.
• Introducing chirality into the channel controllably.
• Measuring the two-terminal asymmetric MR response.
• Comparing the response with standard FM/NM electrode configurations.

Main Results:

• A chirality-dependent asymmetric MR response was observed even with achiral media and nonmagnetic electrodes.
• This response demonstrates the manifestation of MR due to chirality, independent of spin-detecting electrodes.
• The observed effect remained unchanged when using standard FM/NM electrodes and is distinct from EMChA.

Conclusions:

• The observation of chirality-dependent MR in transport experiments does not necessarily imply a direct link between chirality and spin selectivity.
• The CISS effect model may need re-evaluation for systems with non-spin-detecting electrodes.
• This finding broadens the understanding of MR phenomena in chiral and achiral material systems.