Non-magnetic organic/inorganic spin injector at room temperature

Abstract

Spin injection into solid-state devices is commonly performed by use of ferromagnetic metal electrodes. Here, we present a spin injector design without permanent magnet; rather, the spin selectivity is determined by a chiral tunneling barrier. The chiral tunneling barrier is composed of an ultrathin Al2O3 layer that is deposited on top of a chiral self-assembled monolayer (SAM), which consists of cysteine or oligopeptide molecules. The experimentally observed magnetoresistance can be up to 20% at room temperature, and it displays an uncommon asymmetric curve as a function of the applied magnetic field. These findings show that the spin injector transmits only one spin orientation, independent of external magnetic field. The sign of the magnetoresistance depends on the handedness of the molecules in the SAM, which act as a spin filter, and the magnitude of the magnetoresistance depends only weakly on temperature.

Spin Selective Charge Transport through Cysteine Capped CdSe Quantum Dots

“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Interestingly, the magnetoresistance results in this study are opposite in direction to previous measurements that have been reported for self-assembled monolayers (SAMs) composed of cysteine molecules. 43 In order to validate the measurement method used here, magnetoresistance devices like that reported earlier for cysteine SAMs were constructed and the behavior reported earlier in the literature was confirmed. Figure S6 shows the reproduction of these results and they confirm that the MR behavior in the cysteine SAMs are opposite to that found for the cysteine coated QD films.…”

“…Resistance was measured at a constant current (of 1 mA) through the sample. An external magnetic field was varied from -1 T to 1T to generate the magnetoresistance (MR) plot, and the MR is calculated as a percentage; namely 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 of the asymmetric tunnel barrier for the device, namely Au as the bottom contact and Ni as the top contact influencing the spin injection properties (see ref 43 to for a more detailed discussion).…”

Spin Filtering through Single‐Wall Carbon Nanotubes Functionalized with Single‐Stranded DNA

“…Using the spinfiltering property of chiral molecules, ref. [14] has recently demonstrated spin injection in a magnetic tunnel junction (MTJ) device. Here, one of the ferromagnets was replaced by [Au/chiral molecule] composite, which acted as a source of spin-polarized carriers.…”

Electrochemistry of Metalloproteins Attached through Functional Self‐Assembled Monolayers on Gold and Ferromagnetic Electrodes

“…This observation is not unusual, given that similar values have been reportedf or oligopeptides ando ther biomolecules. [13] Similar PMIRRAS spectra wereo btained for Ni/mixed SAM (11-mercaptoundecanoic acid and 1-octanethiol)/Cyt C( Figure S2). Thus, the PMIRRAS resultsunequivocally indicate the formation of well-ordered mixed SAM/Hb heterostructures on the Au and Ni substrates.…”