The European Union Emissions Trading System (EU ETS) is a major pillar of the European energy policy to reduce greenhouse gas emissions. However, the reportedly pervasive frauds in this market are constraining the beneficial role of the EU ETS. In this conceptual paper, we propose to digitalize the EU ETS by distributed ledger technology (DLT), enabling the verification of authenticity and provenance, proof of ownership, and lifecycle traceability of carbon certificates and assets. Our platform allows verifiable credentials to validate emission allowances, real-time tracking of trading participants’ emissions, and the audit trail reporting of the decentralized trading records. Furthermore, we complement the DLT application concept with a structured interdisciplinary evaluation framework. Our framework and analysis aim to stimulate further interdisciplinary research in this area to support regulators, such as the European Commission, in designing effective digital emissions trading systems.

The magnetic anisotropy of epitaxial layered structures of Fe3O4(tFe=4nm)∕GaAs(100), MgO(3nm)∕Fe3O4(tFe=4nm)∕GaAs(100), and Fe3O4(tFe=4nm)∕MgO(3nm)∕Fe3O4(tFe=4nm)∕GaAs(100) was studied by ferromagnetic resonance. It was shown that a predominant in-plane uniaxial magnetic anisotropy and a small fourfold cubic magnetocrystalline anisotropy existed. The in-plane uniaxial anisotropy constant decreased when the MgO layer was covered on Fe3O4∕GaAs, while the cubic anisotropy increased. In the sandwich structures, two resonance peaks were observed. One is similar to that in Fe3O4∕GaAs layer, while another corresponding to Fe3O4 on MgO showed more remarkable fourfold anisotropy and lower uniaxial anisotropy due to smaller mismatch between Fe3O4 and MgO. The interface the Fe3O4 layer is deposited on has dominant effect.

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Patterned magnetic thin films of NiFeCo(3nm)∕Cu(3nm)∕NiFeCo(6nm) spin valve structure with arrays of rectangular elements of micron and submicron sizes have been studied by ferromagnetic resonance. All the rectangular elements have the same aspect ratio of 12 but with different sizes. A set of evenly spaced peaks was observed when the magnetic field was applied near the film normal. The resonant fields of these peaks are in linear proportion with the peak number, and the separation of resonant fields between peaks are approximately inversely proportional to the width of the elements, which suggests that spin waves are excited in the film plane and along the short edge of the elements.