Tuning Magnetic Interactions in 3d-4f Hetero-Bimetallic Surface-Architectures

Recent advancements in surface-confined metal-organic coordination networks (SMON) underscore their potential for creating low-dimensional nanostructures applicable to quantum computing, including qubits and memory devices. These SMON structures are chemically versatile, facilitating precise design of quantum states by tailoring spin center coordination and interactions with substrates. In particular, 3d-4f hetero-bimetallic nanoarchitectures stand out due to their distinctive magnetic exchange interactions between d and f orbitals. Despite these advances, controlling magnetic couplings between spin centers and understanding how different surfaces affect these interactions remain significant challenges for practical solid-state device applications. To address these challenges, our group has developed a new bimetallic SMON using Fe(II)-TCPP (where TCPP is 5,10,15,20-(tetra-4-cyanophenyl)porphyrin) linked to lanthanide atoms (Ln = Dy, Tm) with four-fold symmetry. Previous X-ray absorption spectroscopy (XAS) and magnetic circular dichroism (XMCD) measurements conducted at BOREAS/HECOTR indicated the potential emergence of ferromagnetism in Dy-Fe(II)-TCPP/Au(111). However, the hysteresis cycle, indicative of ferromagnetic coupling, was not observed, and the substrate's role and coupling mechanism were not fully elucidated, due to technical difficulties as described in the experimental report. Therefore, we seek additional beamtime to further investigate these aspects. This research aims to clarify the intricate magnetic coupling mechanisms within these SMON, which will advance quantum computing and open new avenues in materials science. Such insights will enable the precise engineering of molecular systems with tailored magnetic interactions, thereby enhancing the potential for quantum information processing.