scholarly journals Engineering macrocyclic high performance pentagonal bipyramidal Dy(iii) single-ion magnets

2020 ◽  
Vol 56 (80) ◽  
pp. 12037-12040 ◽  
Author(s):  
Angelos B. Canaj ◽  
Sourav Dey ◽  
Claire Wilson ◽  
Oscar Céspedes ◽  
Gopalan Rajaraman ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
High Performance ◽  
Ligand Field ◽  
Equatorial Ligand

We highlight the vast synthetic scope for macrocyclic engineering of magnetic anisotropy, generating a high performance pentagonal bipyramidal Dy(iii) single-ion magnet where the weak equatorial ligand field is created entirely by using a macrocycle.

Is a strong axial crystal-field the only essential condition for a large magnetic anisotropy barrier? The case of non-Kramers Ho(iii) versus Tb(iii )

2018 ◽  
Vol 47 (2) ◽  
pp. 357-366 ◽  
Author(s):  
Sandeep K. Gupta ◽  
Thayalan Rajeshkumar ◽  
Gopalan Rajaraman ◽  
Ramaswamy Murugavel
Keyword(s):  
High Temperature ◽  
Magnetic Anisotropy ◽  
Crystal Field ◽  
Ligand Field ◽  
Essential Condition ◽  
Equatorial Ligand

This study highlights that although strong axiality holds the key for designing high temperature SMMs based on non-Kramers ions, the strength of the equatorial ligand field, although small, cannot be ignored.

scholarly journals Intrinsically weak magnetic anisotropy of cerium in potential hard-magnetic intermetallics

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Anna Galler ◽  
Semih Ener ◽  
Fernando Maccari ◽  
Imants Dirba ◽  
Konstantin P. Skokov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnetic Anisotropy ◽  
High Performance ◽  
Kondo Effect ◽  
Quantitative Description ◽  
Many Body ◽  
Heavy Rare Earth Elements ◽  
Fe Intermetallics ◽  
Full Temperature

AbstractCerium-based intermetallics are currently attracting much interest as a possible alternative to existing high-performance magnets containing scarce heavy rare-earth elements. However, the intrinsic magnetic properties of Ce in these systems are poorly understood due to the difficulty of a quantitative description of the Kondo effect, a many-body phenomenon where conduction electrons screen out the Ce-4f moment. Here, we show that the Ce-4f shell in Ce–Fe intermetallics is partially Kondo screened. The Kondo scale is dramatically enhanced by nitrogen interstitials suppressing the Ce-4f contribution to the magnetic anisotropy, in striking contrast to the effect of nitrogenation in isostructural intermetallics containing other rare-earth elements. We determine the full temperature dependence of the Ce-4f single-ion anisotropy and show that even unscreened Ce-4f moments contribute little to the room-temperature intrinsic magnetic hardness. Our study thus establishes fundamental constraints on the potential of cerium-based permanent magnet intermetallics.

scholarly journals Correlating Axial and Equatorial Ligand Field Effects to the Single-Molecule Magnet Performances of a Family of Dysprosium Bis-Methanediide Complexes

2021 ◽  
Author(s):  
Lewis Thomas-Hargreaves ◽  
Marcus Giansiracusa ◽  
Matthew Gregson ◽  
Emanuele Zanda ◽  
Felix O'Donnell ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Single Molecule ◽  
Ligand Field ◽  
Single Molecule Magnet ◽  
Field Effects ◽  
Equatorial Ligand ◽  
Metal Alkyls

Treatment of the new methanediide-methanide complex [Dy(SCS)(SCSH)(THF)] (1Dy, SCS = {C(PPh2S)2}2-) with alkali metal alkyls and auxillary ethers produces the bis-methanediide complexes [Dy(SCS)2][Dy(SCS)2(K(DME)2)2] (2Dy), [Dy(SCS)2][Na(DME)3] (3Dy) and [Dy(SCS)2][K(2,2,2-cryptand)] (4Dy). For...

scholarly journals High Performance MRAM with Spin-Transfer-Torque and Voltage-Controlled Magnetic Anisotropy Effects

2017 ◽  
Vol 7 (9) ◽  
pp. 929 ◽  
Author(s):  
Hao Cai ◽  
Wang Kang ◽  
You Wang ◽  
Lirida Naviner ◽  
Jun Yang ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
High Performance ◽  
Spin Transfer Torque ◽  
Spin Transfer

The Ligand Field of the Azido Ligand: Insights into Bonding Parameters and Magnetic Anisotropy in a Co(II)–Azido Complex

2015 ◽  
Vol 137 (5) ◽  
pp. 1993-2005 ◽  
Author(s):  
David Schweinfurth ◽  
Michael G. Sommer ◽  
Mihail Atanasov ◽  
Serhiy Demeshko ◽  
Stephan Hohloch ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Ligand Field ◽  
Bonding Parameters

A ligand-field study of the ground spin-state magnetic anisotropy in a family of hexanuclear Mn(iii) single-molecule magnets

2008 ◽  
pp. 2277 ◽  
Author(s):  
Stergios Piligkos ◽  
Jesper Bendix ◽  
Høgni Weihe ◽  
Constantinos J. Milios ◽  
Euan K. Brechin
Keyword(s):  
Magnetic Anisotropy ◽  
Field Study ◽  
Spin State ◽  
Single Molecule ◽  
Ligand Field ◽  
Single Molecule Magnets ◽  
Ground Spin State

Magnetic anisotropy and interaction between f-electronic systems in dinuclear inverted-sandwich-type lanthanide-phthalocyanine complexes

2014 ◽  
Vol 18 (10n11) ◽  
pp. 933-936 ◽  
Author(s):  
Satoshi Tsuchiya ◽  
Akira Fuyuhiro ◽  
Takamitsu Fukuda ◽  
Naoto Ishikawa
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Anisotropy ◽  
Single Molecule ◽  
Magnetic Measurements ◽  
Field Potential ◽  
Magnetic Interaction ◽  
Ligand Field ◽  
Electronic Systems ◽  
Sandwich Type ◽  
Paramagnetic Shifts

The first detection and characterization of magnetic interaction between two 4f electronic systems in the dinuclear "inverted-sandwich-type" phthalocyanine complex with terbium ions and that of dysprosium ions are presented. Temperature dependent magnetic measurements for the diterbium complex, (μ-phthalocyaninato)bis[di(2,2,6,6-tetramethylheptane-3,5-dionato)terbium], show that the value of magnetic susceptibility times temperature, χT, sharply decreases as temperature is lowered, indicating the presence of an antiferromagnetic-type interaction between the Tb 3+ ions in the dinuclear complex. Similar temperature dependence was observed for the corresponding dinuclear dysprosium complex. These results are completely opposite to those observed for Pc triple-decker dinuclear terbium or dysprosium complexes, which are known to function as single molecule magnets. The NMR signals for the protons on the Pc ligand of the diterbium complex show up-field paramagnetic shifts due to the partially-filled 4f shells of the metal ions. This again makes sharp contrast to the triple-deckers, for which large down-field paramagnetic shifts are observed. These intriguing results seen in the NMR and magnetic susceptibility measurements are explained assuming the ligand field potential of the inverted-sandwich complexes gives strong easy-plain-type magnetic anisotropy, where Jz value of the lowest sublevel has a small value, while sandwich-type Pc3Ln2 ( Ln = Tb or Dy ) complexes have a strong easy-axis-type magnetic anisotropy.

scholarly journals Quantifying magnetic anisotropy using X-ray and neutron diffraction

IUCrJ ◽  
2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Emil Andreasen Klahn ◽  
Emil Damgaard-Møller ◽  
Lennard Krause ◽  
Iurii Kibalin ◽  
Arsen Gukasov ◽  
...  
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Magnetic Anisotropy ◽  
Ab Initio ◽  
Single Molecule ◽  
Ligand Field ◽  
Zero Field ◽  
X Ray Diffraction ◽  
Zero Field Splitting ◽  
X Ray

In this work, the magnetic anisotropy in two iso-structural distorted tetrahedral Co(II) complexes, CoX 2tmtu2 [X = Cl(1) and Br(2), tmtu = tetramethylthiourea] is investigated, using a combination of polarized neutron diffraction (PND), very low-temperature high-resolution synchrotron X-ray diffraction and CASSCF/NEVPT2 ab initio calculations. Here, it was found consistently among all methods that the compounds have an easy axis of magnetization pointing nearly along the bisector of the compression angle, with minute deviations between PND and theory. Importantly, this work represents the first derivation of the atomic susceptibility tensor based on powder PND for a single-molecule magnet and the comparison thereof with ab initio calculations and high-resolution X-ray diffraction. Theoretical ab initio ligand field theory (AILFT) analysis finds the d xy orbital to be stabilized relative to the d xz and d yz orbitals, thus providing the intuitive explanation for the presence of a negative zero-field splitting parameter, D, from coupling and thus mixing of d xy and d x 2  −  y 2 . Experimental d-orbital populations support this interpretation, showing in addition that the metal–ligand covalency is larger for Br-ligated 2 than for Cl-ligated 1.

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