scholarly journals Holmium(iii) molecular nanomagnets for optical thermometry exploring the luminescence re-absorption effect

2021 ◽  
Author(s):  
Junhao Wang ◽  
Jakub J. Zakrzewski ◽  
Mikolaj Zychowicz ◽  
Veacheslav Vieru ◽  
Liviu F. Chibotaru ◽  
...  

HoIII complexes bearing organic luminophores and inorganic metalloligands are an effective tool for achieving the unique conjunction of single-molecule magnetism and thermometric luminescence re-absorption phenomenon.

Author(s):  
W. Wernsdorfer

This article describes the quantum phenomena observed in molecular nanomagnets. Molecular nanomagnets, or single-molecule magnets (SMMs), provides a fundamental link between spintronics and molecular electronics. SMMs combine the classic macroscale properties of a magnet with the quantum properties of a nanoscale entity. The resulting field, molecular spintronics, aims at manipulating spins and charges in electronic devices containing one or more molecules. This article first considers molecular nanomagnets and the giant spin model for nanomagnets before discussing the quantum dynamics of a dimer of nanomagnets, resonant photon absorption in Cr7Ni antiferromagnetic rings, and photon-assisted tunnelling in a single-molecule magnet. It also examines environmental decoherence effects in nanomagnets and concludes by highlighting the new trends towards molecular spintronics using junctions and nano-SQUIDs.


Author(s):  
Bing-Wu Wang ◽  
Xin-Yi Wang ◽  
Hao-Ling Sun ◽  
Shang-Da Jiang ◽  
Song Gao

Molecular nanomagnets have been undergoing development for 20 years since the first single-molecule magnet (SMM), Mn 12 Ac, was characterized as the molecule-behaved magnet. The multi-disciplinary scientists promoted the magnetic characteristics to be more suitable for use in information science and spintronics. The concept of molecular nanomagnets has also evolved to include single-chain magnets (SCMs), single-ion magnets (SIMs) and even magnetic molecules that showed only slow magnetic relaxation, in addition to the initial cluster-type SMMs. In this review, several aspects, including SMMs, SCMs and SIMs, are introduced briefly through some representative examples. In particular, the contribution of Chinese chemists is highlighted in the design, synthesis and understanding of various types of molecular nanomagnets.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
F. Petiziol ◽  
A. Chiesa ◽  
S. Wimberger ◽  
P. Santini ◽  
S. Carretta

AbstractMolecular Nanomagnets may enable the implementation of qudit-based quantum error-correction codes which exploit the many spin levels naturally embedded in a single molecule, a promising step towards scalable quantum processors. To fully realize the potential of this approach, a microscopic understanding of the errors corrupting the quantum information encoded in a molecular qudit is essential, together with the development of tailor-made quantum error correction strategies. We address these central points by first studying dephasing effects on the molecular spin qudit produced by the interaction with surrounding nuclear spins, which are the dominant source of errors at low temperatures. Numerical quantum error correction codes are then constructed, by means of a systematic optimization procedure based on simulations of the coupled system-bath dynamics, that provide a striking enhancement of the coherence time of the molecular computational unit. The sequence of pulses needed for the experimental implementation of the codes is finally proposed.


2019 ◽  
Vol 6 (9) ◽  
pp. 2423-2434 ◽  
Author(s):  
Robert Jankowski ◽  
Jakub J. Zakrzewski ◽  
Olga Surma ◽  
Shin-ichi Ohkoshi ◽  
Szymon Chorazy ◽  
...  

Photoluminescent single-molecule magnets are formed in lanthanide(pyrazine N,N′-dioxide) chains with octacyanidometallate(iv) coordination branches playing a crucial role in sensitized NIR emission.


2022 ◽  
Author(s):  
Michał Magott ◽  
Maria Brzozowska ◽  
Stanisław Baran ◽  
Veacheslav Vieru ◽  
Dawid Pinkowicz

The best performing molecular nanomagnets are currently designed by carefully arranging p-element donor atoms (usually carbon, nitrogen and/or oxygen) around the central magnetic ion. Inspired by the structure of the hardest intermetallic magnet SmCo5, we have demonstrated a nanomagnetic molecule where the central lanthanide (Ln) ion Er is coordinated solely by three transition metal (TM) ions in a perfectly trigonal planar fashion. The molecule [Er(ReCp2)3] (ErRe3) constitutes the first example of a molecular nanomagnet (MNM; or single molecule magnet SMM) with unsupported Ln-TM bonds and paves the way towards molecular intermetallics with strong direct magnetic exchange interactions. Such interactions are believed to be crucial for quenching the quantum tunneling of magnetization which limits the application of Ln-SMMs as sub-nanometer magnetic memory units.


2021 ◽  
Vol 7 (6) ◽  
pp. 79
Author(s):  
Michal Liberka ◽  
Kseniia Boidachenko ◽  
Jakub J. Zakrzewski ◽  
Mikolaj Zychowicz ◽  
Junhao Wang ◽  
...  

One of the pathways toward luminescent single-molecule magnets (SMMs) is realized by the self-assembly of lanthanide(3+) ions with cyanido transition metal complexes. We report a novel family of emissive SMMs, {YbIII(4-pyridone)4[FeII(phen)2(CN)2]2}(CF3SO3)3·solv (solv = 2MeCN, 1·MeCN; 2AcrCN, 1·AcrCN; 2PrCN, 1·PrCN; 2MalCN·1MeOH; 1·MalCN; MeCN = acetonitrile, AcrCN = acrylonitrile, PrCN = propionitrile, MalCN = malononitrile). They are based on paramagnetic YbIII centers coordinating diamagnetic [FeII(phen)2(CN)2] metalloligands but differ in the nitrile solvents of crystallization. They exhibit a field-induced slow magnetic relaxation dominated by a Raman process, without an Orbach relaxation as indicated by AC magnetic data and the ab initio calculations. The Raman relaxation is solvent-dependent as represented by the power “n” of the BRamanTn contribution varying from 3.07(1), to 2.61(1), 2.37(1), and 1.68(4) for 1·MeCN, 1·PrCN, 1·AcrCN, and 1·MalCN, respectively, while the BRaman parameter adopts the opposite trend. This was correlated with the variation of phonon modes schemes, including the number of available vibrational modes and their energies, dependent on the increasing complexity of the applied nitrile. 1·MeCN and 1·MalCN show the additional T-independent relaxation assignable to dipole-dipole interactions as confirmed by its suppression in 1·AcrCN and 1·PrCN revealing longer Yb–Yb distances and the disappearance in the LuIII-diluted 1·MeCN@Lu. All compounds exhibit YbIII–centered near-infrared photoluminescence sensitized by organic ligands.


Author(s):  
Robert Jankowski ◽  
Jakub J. Zakrzewski ◽  
Mikolaj Zychowicz ◽  
Junhao Wang ◽  
Yurie Oki ◽  
...  

Lanthanide(III) single-molecule magnets (Ln-SMMs) offer the fruitful conjunction of magnetic and photoluminescent properties originating from their single-ion anisotropy and emissive f-f electronic transitions. The flexibility of lanthanide(III)-based coordination systems is...


2014 ◽  
Vol 70 (a1) ◽  
pp. C274-C274
Author(s):  
Bing-Wu Wang ◽  
Zhe-Ming Wang ◽  
Song Gao

The single-molecule magnets (SMMs) are attracting the increasing interesting due to their potential applications in high density information storage, quantum computing, molecular spintronics, and magnetic refrigeration. This field provides scientists a possible access into the crossover of the classical and quantum world, and a wonderful model to study the fascinating magnetic properties between microscopic and macroscopic materials, such as slow magnetization relaxation and quantum tunneling effect. After the milestone discovery of the first single-molecule magnets (SMMs) Mn12ac, many new SMMs were structurally and magnetically characterized. The most studied systems are mainly traditional coordination compounds with polynuclear structures. However, for the difficulties in the control of magnetic anisotropy and exchange coupling interactions of the cluster-type molecules, Mn12ac molecule is still one of the most important SMMs with the high relaxation barrier. From 2011 [1-3], we explored an organometallic sandwich molecule, Cp*ErCOT(Cp* = pentamethylcyclopenta-dienide; COT = cyclooctatetraenide), which behaves as a single-ion magnets, into the field of molecular nanomagnets. It opened a door of SMMs to the chemists in organometallic chemistry. Recently, we found some new sandwich or half-sandwich lanthanide organometallic molecules could also show the slow relaxation of magnetization. We hope these systems can provide new understandings of slow magnetic relaxation and new clues on the design and synthesis of molecular nanomagnets. This work was supported by NSFC, the National Basic Research Program of China.


2021 ◽  
Vol 11 (16) ◽  
pp. 7510
Author(s):  
Tomasz Blachowicz ◽  
Andrea Ehrmann

Molecular magnets are a relatively new class of purely organic or metallo-organic materials, showing magnetism even without an external magnetic field. This interdisciplinary field between chemistry and physics has been gaining increased interest since the 1990s. While bulk molecular magnets are usually hard to build because of their molecular structures, low-dimensional molecular magnets are often easier to construct, down to dot-like (zero-dimensional) structures, which are investigated by different scanning probe technologies. On these scales, new effects such as superparamagnetic behavior or coherent switching during magnetization reversal can be recognized. Here, we give an overview of the recent advances in molecular nanomagnets, starting with single-molecule magnets (0D), typically based on Mn12, Fe8, or Mn4, going further to single-chain magnets (1D) and finally higher-dimensional molecular nanomagnets. This review does not aim to give a comprehensive overview of all research fields dealing with molecular nanomagnets, but instead aims at pointing out diverse possible materials and effects in order to stimulate new research in this broad field of nanomagnetism.


Author(s):  
George C. Ruben

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.


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