Magnetoresistance effect based on spin-selective transport in nanodevices using chiral molecules

Recently, chirality-induced spin selectivity (CISS) has been observed in chiral molecules and is attractive for application in magnetoresistance (MR) devices. In this study, we fabricate CISS-based nanodevices consisting of chiral molecules sandwiched between Ni₇₈Fe₂₂ and Au electrodes. Prior to device fabrication, we have synthesized the chiral molecule <i>N</i>-(3<i>S</i>)-3,7-dimethyloctyl[1]benzothieno[3,2-<i>b</i>]benzothiophene-2-carboxyamide (<i>S</i>-BTBT-CONHR) and established a method for fabricating nanodevice electrodes. We have successfully observed a high degree of spin selectivity in <i>S</i>-BTBT-CONHR thin films using magnetic conductive atomic force microscopy (mc-AFM). By combining chiral molecules with our advanced nanofabrication technique, we have successfully fabricated Au/<i>S</i>-BTBT-CONHR/Ni₇₈Fe₂₂ nanodevices and observed the MR effect in the fabricated devices under a low magnetic field at room temperature. These MR curves correspond to the magnetization states of the Ni₇₈Fe₂₂ electrode, indicating that the CISS-based MR effect is successfully observed in the nanodevices under a low magnetic field. This study can lead to the development of CISS-based MR devices under low magnetic fields and provide new insights into the CISS effect mechanism on devices.