  Chiral-induced spin selectivity (CISS), whereby helical molecules polarize
the spin of electrical current, is an intriguing effect with potential
applications in nanospintronics. In this nascent field, the study of
paramagnetic chiral molecules, which could introduce another degree of freedom
in the control of the spin transport, remains so far unexplored. To address
this challenge, herein, we propose the use of self-assembled monolayers of
helical lanthanide-binding peptides. In order to elucidate the effect of the
paramagnetic nuclei, monolayers of the peptide coordinating paramagnetic or
diamagnetic ions are prepared. By means of spin-dependent electrochemistry,
CISS effect is demonstrated by cyclic voltammetry and impedance measurements
for both samples. Additionally, an implementation of the standard liquid-metal
drop electron transport setup has been carried out, demonstrating their
suitability for solid-state devices. Remarkably, the inclusion of a
paramagnetic center in the peptide increases the spin polarization as
independently proved by different techniques. These findings permit the
inclusion of magnetic biomolecules in the CISS field, paving the way to their
implementation in a new generation of spintronic nanodevices.
