Temperature-Enhanced Coercive Field by Chiral Molecules

TL;DR

This study reveals that the coercive field enhancement caused by chiral molecules on magnetic surfaces increases with temperature, challenging classical expectations and suggesting vibronic contributions to the CISS effect.

Contribution

It demonstrates that spin-dependent interactions between chiral molecules and magnetic surfaces can strengthen at higher temperatures, providing new insights into the microscopic mechanisms of CISS.

Findings

Magnetic coercivity increases by 1 mT over 60°C with chiral molecules.

Temperature enhances the spin-dependent effects of chiral molecules on magnetic surfaces.

Results support a vibronic, electron-phonon interaction contribution to CISS.

Abstract

The chiral-induced spin selectivity (CISS) effect demonstrates a strong coupling between electron spin and molecular chirality, enabling spin-controlled interactions between chiral molecules and magnetic surfaces. While CISS experiments have revealed robust changes in the spin-polarization properties of magnetic materials upon chiral molecular adsorption, the temperature dependence of these effects remains poorly understood. Here, we investigate the temperature dependence of the chirality-induced increase in magnetic coercivity by ribose-aminooxazoline (RAO) crystals on ferromagnetic surfaces. RAO was selected as a conglomerate-forming, thermodynamically stable crystalline chiral organic molecule with prebiotic relevance that has previously been shown to induce strong spin-dependent changes in magnetic minerals. Contrary to classical expectations that magnetic coercivity weakens at elevated temperatures, we observe a significant increase in magnetic coercivity (1 mT over a 60 C temperature change) with increasing temperature. These results support a vibronic contribution to CISS arising from electron-phonon interactions and demonstrate that spin-dependent interactions between chiral molecules and magnetic surfaces can become more effective at higher temperatures, providing new insight into the microscopic origins of CISS and the environmental robustness of spin-controlled asymmetric processes.