Disentangling magnetic hardening and molecular spin chain contributions to exchange bias in ferromagnet/molecule bilayers

We performed SQUID and FMR magnetometry experiments to clarify the relationship between two reported magnetic exchange effects arising from interfacial spin-polarized charge transfer within ferromagnetic metal (FM)/molecule bilayers: the magnetic hardening effect, and spinterface-stabilized molecular spin chains. To disentangle these effects, both of which can affect the FM magnetization reversal, we tuned the metal phthalocyanine molecule central site's magnetic moment to selectively enhance or suppress the formation of spin chains within the molecular film. We find that both effects are distinct, and additive. In the process, we 1) extended the list of FM/molecule candidate pairs that are known to generate magnetic exchange effects, 2) experimentally confirmed the predicted increase in anisotropy upon molecular adsorption; and 3) showed that spin chains within the molecular film can enhance magnetic exchange. This magnetic ordering within the organic layer implies a structural ordering. Thus, by distengangling the magnetic hardening and exchange bias contributions, our results confirm, as an echo to progress regarding inorganic spintronic tunnelling, that the milestone of spintronic tunnelling across structurally ordered organic barriers has been reached through previous magnetotransport experiments. This paves the way for solid-state devices studies that exploit the quantum physical properties of spin chains, notably through external stimuli.Comment: Non

Additional file 1: Supplementary data on the synthesis of BODIPY-BBN, its in-vitro characterization and its in-vivo biodistribution and stability. Figure S1. of Development of a clickable bimodal fluorescent/PET probe for in vivo imaging

Synthesis and analytical data of BODIPY-azide 1. Figure S2. Synthesis of BODIPY-BBN 5 using CuAAC click chemistry. Figure S3. In vitro cell binding study of BODIPY-BBN 5 using GRPr overexpressing PC-3 cells. Figure S4. Quantification of tumor uptake comparing fluorescent imaging as well as gamma-counting. Figure S5. In vivo small animal PET/CT images (60 min) of PC-3 tumor-bearing nude mice after intravenous injection of 18F-BODIPY-BBN 3 (55 ± 10 μCi) in PBS (4 % DMSO, 200 μL). Figure S6. Percent intact fluorescent 19F-BODIPY-BBN in human serum at different time points (0, 15, 30, 45, and 60 min) after incubation at 37 °C

Additional file 1: of Discriminating radiation injury from recurrent tumor with [18F]PARPi and amino acid PET in mouse models

Figures S1–S9 and Tables S1–S6. (PDF 14174 kb

Spin-Dependent Hybridization between Molecule and Metal at Room Temperature through Interlayer Exchange Coupling

We experimentally and theoretically show that the magnetic coupling at room temperature between paramagnetic Mn within manganese phthalocyanine molecules and a Co layer persists when separated by a Cu spacer. The molecule’s magnetization amplitude and direction can be tuned by varying the Cu–spacer thickness and evolves according to an interlayer exchange coupling mechanism. <i>Ab initio</i> calculations predict a highly spin-polarized density of states at the Fermi level of this metal-molecule interface, thereby strengthening prospective spintronics applications

High Spin Polarization at Ferromagnetic Metal–Organic Interfaces: A Generic Property

A high spin polarization of states around the Fermi level, <i>E</i>_F, at room temperature has been measured in the past at the interface between a few molecular candidates and the ferromagnetic metal Co. Is this promising property for spintronics limited to these candidates? Previous reports suggested that certain conditions, such as strong ferromagnetism, i.e., a fully occupied spin-up d band of the ferromagnet, or the presence of π bonds on the molecule, i.e., molecular conjugation, needed to be met. What rules govern the presence of this property? We have performed spin-resolved photoemission spectroscopy measurements on a variety of such interfaces. We find that this property is robust against changes to the molecule and ferromagnetic metal’s electronic properties, including the aforementioned conditions. This affirms the generality of highly spin-polarized states at the interface between a ferromagnetic metal and a molecule and augurs bright prospects toward integrating these interfaces within organic spintronic devices