A Model for Single-Molecule Information Storage

The molecular magnetorefrigerant materials for low-temperature magnetic refrigeration and single-molecule magnets for high-density information storage and quantum computing have received extensive attention from chemists and magnetic experts. Lanthanide ions with...

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Leveraging Surface Siloxide Electronics to Enhance Relaxation Properties of a Single-Molecule Magnet

10.26434/chemrxiv.12818183 ◽

2020 ◽

Author(s):

Maciej Korzynski ◽

Zachariah Berkson ◽

Boris Le Guennic ◽

Olivier Cador ◽

Christophe Copéret

Keyword(s):

Single Molecule ◽

Relaxation Times ◽

Device Fabrication ◽

Information Storage ◽

Commercial Application ◽

Surface Immobilization ◽

Single Molecule Magnets ◽

Magnetization Relaxation ◽

Surface Deposition ◽

Magnitude Increase

Single-molecule magnets (SMMs) hold promise for unmatched information storage density as well as applications in quantum computing and spintronics. To date, the most successful SMMs are organometallic lanthanide complexes. However, their surface immobilization, one of the requirements for device fabrication and commercial application, remains challenging due to sensitivity of magnetic properties to small changes in the electronic structure of the parent SMM. Thus, finding controlled approaches to SMM surface deposition is a timely challenge. In this contribution we apply the concept of isolobality to identify siloxides present at the surface of partially dehydroxylated silica as a suitable replacement for archetypal ligand architectures in organometallic SMMs. We demonstrate theoretically and experimentally that isolated siloxide anchorages not only enable successful immobilization, but also lead to two-orders-of-magnitude increase in magnetization relaxation times and provide magnetic site dilution.

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Breaching the Axial Limits in Ln(III) Single-Ion Magnets Using External Electric Field

10.26434/chemrxiv.12403124 ◽

2020 ◽

Author(s):

Arup Sarkar ◽

Rajaraman Gopalan

Keyword(s):

Electric Field ◽

External Electric Field ◽

Barrier Height ◽

Electric Fields ◽

Single Molecule ◽

Information Storage ◽

Fine Tuning ◽

Ligand Field ◽

Nano Technology ◽

Technology Applications

Single-Molecule Magnets have potential applications in several nano-technology applications including in high-dense information storage devices and realization of this potential application lies in enhancing the barrier height for magnetization reversal (Ueff). Recent literature examples suggest that the maximum values that one can obtain using a ligand field are already accomplished. Here we have explored using a combination of DFT and ab initio CASSCF calculations, the way to enhance the barrier height using an oriented external electric field for top three Single-ion Magnets ([Dy(Py)5(OtBu)2]+ (1) and [Er{N(SiMe3)2}3Cl]- (2) and [Dy(CpMe3)Cl] (3)). For the first time our study reveals that, for apt molecules, if appropriate direction and value of electric fields are chosen, the barrier height could be enhanced twice that of the limit set by the ligand field. This novel non-chemical-fine tuning approach to modulate the magnetic anisotropy is expected to yield new generation SIMs.

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mRNA Trafficking in the Nervous System: A Key Mechanism of the Involvement of Activity-Regulated Cytoskeleton-Associated Protein (Arc) in Synaptic Plasticity

Neural Plasticity ◽

10.1155/2021/3468795 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Michal Fila ◽

Laura Diaz ◽

Joanna Szczepanska ◽

Elzbieta Pawlowska ◽

Janusz Blasiak

Keyword(s):

Synaptic Plasticity ◽

Single Molecule ◽

Memory Consolidation ◽

De Novo ◽

Intracellular Localization ◽

Specific Antigen ◽

Information Storage ◽

Synaptic Activity ◽

Mrna Trafficking ◽

And Behavior

Synaptic activity mediates information storage and memory consolidation in the brain and requires a fast de novo synthesis of mRNAs in the nucleus and proteins in synapses. Intracellular localization of a protein can be achieved by mRNA trafficking and localized translation. Activity-regulated cytoskeleton-associated protein (Arc) is a master regulator of synaptic plasticity and plays an important role in controlling large signaling networks implicated in learning, memory consolidation, and behavior. Transcription of the Arc gene may be induced by a short behavioral event, resulting in synaptic activation. Arc mRNA is exported into the cytoplasm and can be trafficked into the dendrite of an activated synapse where it is docked and translated. The structure of Arc is similar to the viral GAG (group-specific antigen) protein, and phylogenic analysis suggests that Arc may originate from the family of Ty3/Gypsy retrotransposons. Therefore, Arc might evolve through “domestication” of retroviruses. Arc can form a capsid-like structure that encapsulates a retrovirus-like sentence in the 3 ′ -UTR (untranslated region) of Arc mRNA. Such complex can be loaded into extracellular vesicles and transported to other neurons or muscle cells carrying not only genetic information but also regulatory signals within neuronal networks. Therefore, Arc mRNA inter- and intramolecular trafficking is essential for the modulation of synaptic activity required for memory consolidation and cognitive functions. Recent studies with single-molecule imaging in live neurons confirmed and extended the role of Arc mRNA trafficking in synaptic plasticity.

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STM STUDY OF THE ADSORPTION OF SINGLE-MOLECULE MAGNET Fe4 ON Bi(111) SURFACE

Surface Review and Letters ◽

10.1142/s0218625x15500602 ◽

2015 ◽

Vol 22 (05) ◽

pp. 1550060 ◽

Cited By ~ 1

Author(s):

YUAN LUO ◽

LAN LUO ◽

KAI SUN ◽

MIN-LONG TAO ◽

JUN-ZHONG WANG

Keyword(s):

Single Molecule ◽

Scanning Tunneling Spectroscopy ◽

Information Storage ◽

Scanning Tunneling ◽

Single Molecule Magnets ◽

Quantum Tunneling Of Magnetization ◽

Potential Applications ◽

Temperature Scanning ◽

Molecular Morphology ◽

Homo Lumo

Single-molecule magnets (SMMs) have unique magnetic properties such as quantum tunneling of magnetization and quantum coherent oscillation, which have potential applications in quantum computation and information storage. In this paper, using the tip-deposition method, we have grafted individual Fe 4 molecules onto the semi-metallic Bi (111) surface. Low temperature scanning tunneling microscope (LT-STM) was used to characterize the molecular morphology and electronic structures. It was found that individual Fe 4 molecules reveal a triangle shape, which is consistent with the molecular structure of Fe 4. Scanning tunneling spectroscopy (STS) analysis indicated that the HOMO–LUMO gap is 0.49 eV. These studies provide direct information about the adsorption of individual SMMs on semi-metal surfaces.

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Leveraging Surface Siloxide Electronics to Enhance Relaxation Properties of a Single-Molecule Magnet

10.26434/chemrxiv.12818183.v2 ◽

2021 ◽

Author(s):

Maciej Korzynski ◽

Zachariah Berkson ◽

Boris Le Guennic ◽

Olivier Cador ◽

Christophe Copéret

Keyword(s):

Single Molecule ◽

Relaxation Times ◽

Device Fabrication ◽

Information Storage ◽

Commercial Application ◽

Surface Immobilization ◽

Single Molecule Magnets ◽

Magnetization Relaxation ◽

Surface Deposition ◽

Magnitude Increase

Single-molecule magnets (SMMs) hold promise for unmatched information storage density as well as applications in quantum computing and spintronics. To date, the most successful SMMs are organometallic lanthanide complexes. However, their surface immobilization, one of the requirements for device fabrication and commercial application, remains challenging due to sensitivity of magnetic properties to small changes in the electronic structure of the parent SMM. Thus, finding controlled approaches to SMM surface deposition is a timely challenge. In this contribution we apply the concept of isolobality to identify siloxides present at the surface of partially dehydroxylated silica as a suitable replacement for archetypal ligand architectures in organometallic SMMs. We demonstrate theoretically and experimentally that isolated siloxide anchorages not only enable successful immobilization, but also lead to two-orders-of-magnitude increase in magnetization relaxation times and provide magnetic site dilution.

Download Full-text

Breaching the Axial Limits in Ln(III) Single-Ion Magnets Using External Electric Field

10.26434/chemrxiv.12403124.v1 ◽

2020 ◽

Author(s):

Arup Sarkar ◽

Rajaraman Gopalan

Keyword(s):

Electric Field ◽

External Electric Field ◽

Barrier Height ◽

Electric Fields ◽

Single Molecule ◽

Information Storage ◽

Fine Tuning ◽

Ligand Field ◽

Nano Technology ◽

Technology Applications

Single-Molecule Magnets have potential applications in several nano-technology applications including in high-dense information storage devices and realization of this potential application lies in enhancing the barrier height for magnetization reversal (Ueff). Recent literature examples suggest that the maximum values that one can obtain using a ligand field are already accomplished. Here we have explored using a combination of DFT and ab initio CASSCF calculations, the way to enhance the barrier height using an oriented external electric field for top three Single-ion Magnets ([Dy(Py)5(OtBu)2]+ (1) and [Er{N(SiMe3)2}3Cl]- (2) and [Dy(CpMe3)Cl] (3)). For the first time our study reveals that, for apt molecules, if appropriate direction and value of electric fields are chosen, the barrier height could be enhanced twice that of the limit set by the ligand field. This novel non-chemical-fine tuning approach to modulate the magnetic anisotropy is expected to yield new generation SIMs.

Download Full-text

Leveraging Surface Siloxide Electronics to Enhance Relaxation Properties of a Single-Molecule Magnet

10.26434/chemrxiv.12818183.v3 ◽

2021 ◽

Author(s):

Maciej Korzynski ◽

Zachariah Berkson ◽

Boris Le Guennic ◽

Olivier Cador ◽

Christophe Copéret

Keyword(s):

Single Molecule ◽

Relaxation Times ◽

Device Fabrication ◽

Information Storage ◽

Commercial Application ◽

Surface Immobilization ◽

Single Molecule Magnets ◽

Magnetization Relaxation ◽

Surface Deposition ◽

Magnitude Increase

Single-molecule magnets (SMMs) hold promise for unmatched information storage density as well as applications in quantum computing and spintronics. To date, the most successful SMMs are organometallic lanthanide complexes. However, their surface immobilization, one of the requirements for device fabrication and commercial application, remains challenging due to sensitivity of magnetic properties to small changes in the electronic structure of the parent SMM. Thus, finding controlled approaches to SMM surface deposition is a timely challenge. In this contribution we apply the concept of isolobality to identify siloxides present at the surface of partially dehydroxylated silica as a suitable replacement for archetypal ligand architectures in organometallic SMMs. We demonstrate theoretically and experimentally that isolated siloxide anchorages not only enable successful immobilization, but also lead to two-orders-of-magnitude increase in magnetization relaxation times.

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Magnetic hysteresis up to 80 kelvin in a dysprosium metallocene single-molecule magnet

Science ◽

10.1126/science.aav0652 ◽

2018 ◽

Vol 362 (6421) ◽

pp. 1400-1403 ◽

Cited By ~ 513

Author(s):

Fu-Sheng Guo ◽

Benjamin M. Day ◽

Yan-Cong Chen ◽

Ming-Liang Tong ◽

Akseli Mansikkamäki ◽

...

Keyword(s):

Single Molecule ◽

Magnetic Hysteresis ◽

Information Storage ◽

Blocking Temperature ◽

Wave Number ◽

Magnetic Memory ◽

Single Molecule Magnets ◽

Single Molecule Magnet ◽

Chemical Strategy ◽

Lower Size

Single-molecule magnets (SMMs) containing only one metal center may represent the lower size limit for molecule-based magnetic information storage materials. Their current drawback is that all SMMs require liquid-helium cooling to show magnetic memory effects. We now report a chemical strategy to access the dysprosium metallocene cation [(CpiPr5)Dy(Cp*)]+ (CpiPr5, penta-iso-propylcyclopentadienyl; Cp*, pentamethylcyclopentadienyl), which displays magnetic hysteresis above liquid-nitrogen temperatures. An effective energy barrier to reversal of the magnetization of Ueff = 1541 wave number is also measured. The magnetic blocking temperature of TB = 80 kelvin for this cation overcomes an essential barrier toward the development of nanomagnet devices that function at practical temperatures.

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Activation-triggered subunit exchange between CaMKII holoenzymes facilitates the spread of kinase activity

eLife ◽

10.7554/elife.01610 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 48

Author(s):

Margaret Stratton ◽

Il-Hyung Lee ◽

Moitrayee Bhattacharyya ◽

Sune M Christensen ◽

Luke H Chao ◽

...

Keyword(s):

Single Molecule ◽

Kinase Activity ◽

Exchange Process ◽

Memory Formation ◽

Information Storage ◽

Remarkable Property ◽

Subunit Exchange ◽

Calmodulin Binding ◽

Microscopy Technique ◽

Dynamics Simulations

The activation of the dodecameric Ca2+/calmodulin dependent kinase II (CaMKII) holoenzyme is critical for memory formation. We now report that CaMKII has a remarkable property, which is that activation of the holoenzyme triggers the exchange of subunits between holoenzymes, including unactivated ones, enabling the calcium-independent phosphorylation of new subunits. We show, using a single-molecule TIRF microscopy technique, that the exchange process is triggered by the activation of CaMKII, and that exchange is modulated by phosphorylation of two residues in the calmodulin-binding segment, Thr 305 and Thr 306. Based on these results, and on the analysis of molecular dynamics simulations, we suggest that the phosphorylated regulatory segment of CaMKII interacts with the central hub of the holoenzyme and weakens its integrity, thereby promoting exchange. Our results have implications for an earlier idea that subunit exchange in CaMKII may have relevance for information storage resulting from brief coincident stimuli during neuronal signaling.

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