Magnetic Properties and Structure of Metallic Multilayers Investigated by NMR

1997 ◽  
Vol 475 ◽  
Author(s):  
P. Panissod ◽  
C. Mèny ◽  
M. Wójcik ◽  
E. Jedryka
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Magnetic Coupling ◽  
Structural Features ◽  
Magnetic Multilayers ◽  
Topological Order ◽  
Metallic Multilayers ◽  
Local Magnetization ◽  
Structural Investigations ◽  
Electronic Moment

ABSTRACTAs a probe of the short range chemical and topological order, NMR is useful for structural investigations of magnetic multilayers (interface structure and composition, bulk phases and defects, strains). The magnetic character of the raw data makes it also possible to study local magnetic properties of these composite systems, and to correlate them with local structural features. The hyperfine field is the first output of an NMR experiment which gives a direct insight on the local magnetization in ferromagnets. NMR is also sensitive to the restoring torque exerted on the electronic moment by the local magnetic anisotropy and/or exchange and dipolar couplings. Combined with the fact that the various parts of a sample (atomic planes involved in the interfaces, bulk phases and bulk defects) can be discriminated in the spectra, the magnetic information contained in the data allows to probe quantitatively or, at least, to place on a relative scale, the different magnetic responses of the different parts of a sample. We present here the relevant results which we have obtained in the course of our investigations of Co based multilayers and spin valves (interface magnetic profiles, inhomogeneities of magnetic anisotropy and of magnetic coupling).

Effects of Heat Treatment Conditions on Magnetic Properties and Structural Features of Nanocrystalline Fe79Zr10N11 Films

2009 ◽  
Vol 152-153 ◽  
pp. 70-74 ◽  
Author(s):  
E.N. Sheftel ◽  
Rauf S. Iskhakov ◽  
S.V. Komogortsev ◽  
P.K. Sidorenko ◽  
Nikolai S. Perov
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Structural Features ◽  
Soft Magnetic ◽  
Exchange Correlation ◽  
Calculation Technique ◽  
Treatment Conditions ◽  
Random Magnetic Anisotropy ◽  
Anisotropy Model

Data on the random magnetic anisotropy and exchange correlation length in soft magnetic nanocrystalline Fe79Zr10N11 films were obtained using a calculation technique in frame of the random magnetic anisotropy model. The calculations are performed using approach magnetization to saturation curves. The local magnetic anisotropy fields (Ha), and magnetic anisotropy correlation radii (Rс) reduced to =(A/K)1/2 were determined for the films annealed at 475 and 6000 C for 0.5, 1, 2, and 3 h. The correlation Hc ~(Rc/)3 for the all annealed films was found.

Engineering magnetic anisotropy and magnetization switching in multilayers by strain

2017 ◽  
Vol 19 (5) ◽  
pp. 4125-4130 ◽  
Author(s):  
Kun Tao ◽  
Pengfei Liu ◽  
Qing Guo ◽  
Liya Shen ◽  
Desheng Xue ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Ab Initio ◽  
Metallic Multilayers ◽  
Magnetization Switching

The effect of the strain on the magnetic properties of metallic multilayers has been investigated by ab initio studies.

scholarly journals Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2792
Author(s):  
Isabel Castro ◽  
M. Luisa Calatayud ◽  
Marta Orts-Arroyo ◽  
Nicolás Moliner ◽  
Nadia Marino ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Coupling ◽  
Structural Features ◽  
Pyrazole Derivatives ◽  
Spin Hamiltonian ◽  
Temperature Range ◽  
Coordination Center

Two novel copper(II) complexes of formulas {[Cu(4-Hmpz)4][Cu(4-Hmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(ClO4)2]}n (1) and {[Cu(3,4,5-Htmpz)4]2[Cu(3,4,5-Htmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(H2O)(ClO4)]2[Cu2(3,4,5-Htmpz)4(µ-ox-κ2O1,O2:κ2O2′,O1′)]}(ClO4)4·6H2O (2) have been obtained by using 4-methyl-1H-pyrazole (4-Hmpz) and 3,4,5-trimethyl-1H-pyrazole (3,4,5-Htmpz) as terminal ligands and oxalate (ox) as the polyatomic inverse coordination center. The crystal structure of 1 consists of perchlorate counteranions and cationic copper(II) chains with alternating bis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) and tetrakis(pyrazole)copper(II) fragments. The crystal structure of 2 is made up of perchlorate counteranions and cationic centrosymmetric hexanuclear complexes where an inner tetrakis(pyrazole)(µ-κ2O1,O2:κ2O2′,O1′-oxalato)dicopper(II) entity and two outer mononuclear tetrakis(pyrazole)copper(II) units are linked through two mononuclear aquabis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) units. The magnetic properties of 1 and 2 were investigated in the temperature range 2.0–300 K. Very weak intrachain antiferromagnetic interactions between the copper(II) ions through the µ3-ox-κ2O1,O2:κO2′:κO1′ center occur in 1 [J = −0.42(1) cm−1, the spin Hamiltonian being defined as H = −J∑S1,i · S2,i+1], whereas very weak intramolecular ferromagnetic [J = +0.28(2) cm−1] and strong antiferromagnetic [J’ = −348(2) cm−1] couplings coexist in 2 which are mediated by the µ3-ox-κ2O1,O2:κO2′:κO1′ and µ-ox-κ2O1,O2:κ2O2′,O1′ centers, respectively. The variation in the nature and magnitude of the magnetic coupling for this pair of oxalato-centered inverse copper(II) complexes is discussed in the light of their different structural features, and a comparison with related oxalato-centered inverse copper(II)-pyrazole systems from the literature is carried out.

Dynamics and magnetic properties of NO molecules encapsulated in open-cage fullerene derivatives evidenced by low temperature heat capacity

2021 ◽  
Author(s):  
Yoji Horii ◽  
Hal Suzuki ◽  
Yuji Miyazaki ◽  
Motohiro Nakano ◽  
Shota Hasegawa ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Magnetic Anisotropy ◽  
Fullerene Derivatives ◽  
Molecular Cages ◽  
Temperature Heat ◽  
Low Temperature Heat Capacity

Heat capacity analyses revealed dynamics and magnetic anisotropy of NO molecules confined in molecular cages.

Structural insights into the repair mechanism of AGT for methyl-induced DNA damage

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rajendra P. Koirala ◽  
Rudramani Pokhrel ◽  
Prabin Baral ◽  
Purushottam B. Tiwari ◽  
Prem P. Chapagain ◽  
...  
Keyword(s):  
Covalent Bond ◽  
Cancer Therapeutics ◽  
Md Simulations ◽  
Structural Features ◽  
Umbrella Sampling ◽  
Repair Mechanism ◽  
Structural Investigations ◽  
Methylated Dna ◽  
Dna Base ◽  
Dna Alkyltransferase

Abstract Methylation induced DNA base-pairing damage is one of the major causes of cancer. O6-alkylguanine-DNA alkyltransferase (AGT) is considered a demethylation agent of the methylated DNA. Structural investigations with thermodynamic properties of the AGT-DNA complex are still lacking. In this report, we modeled two catalytic states of AGT-DNA interactions and an AGT-DNA covalent complex and explored structural features using molecular dynamics (MD) simulations. We utilized the umbrella sampling method to investigate the changes in the free energy of the interactions in two different AGT-DNA catalytic states, one with methylated GUA in DNA and the other with methylated CYS145 in AGT. These non-covalent complexes represent the pre- and post-repair complexes. Therefore, our study encompasses the process of recognition, complex formation, and separation of the AGT and the damaged (methylated) DNA base. We believe that the use of parameters for the amino acid and nucleotide modifications and for the protein-DNA covalent bond will allow investigations of the DNA repair mechanism as well as the exploration of cancer therapeutics targeting the AGT-DNA complexes at various functional states as well as explorations via stabilization of the complex.

Structural diversity and magnetic properties of six ferrocenyl monocarboxylate Mn(ii), Ni(ii) and Co(ii) complexes with 1D aqua, carboxyl or dinuclear hydroxyl bridges

CrystEngComm ◽  
2021 ◽  
Author(s):  
Misbha Rafiq Khan ◽  
Xiaoge Niu ◽  
Tianling Chen ◽  
Yan Liu ◽  
Zhongyi Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Coupling ◽  
Structural Diversity ◽  
Different Types ◽  
Structure Diversity

Six ferrocenyl monocarboxylate Mn(ii), Ni(ii) and Co(ii) complexes with different types of magnetic coupling bridges were synthesized successfully. 1–6 display intriguing structure diversity and magnetic properties.

scholarly journals Exploring the magnetic properties and magnetic coupling in SrFe12O19/Co1-xZnxFe2O4 nanocomposites

2021 ◽  
pp. 168095
Author(s):  
P. Maltoni ◽  
T. Sarkar ◽  
G. Barucca ◽  
G. Varvaro ◽  
D. Peddis ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Coupling

scholarly journals Visualizing atomic structure and magnetism of 2D magnetic insulators via tunneling through graphene

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhizhan Qiu ◽  
Matthew Holwill ◽  
Thomas Olsen ◽  
Pin Lyu ◽  
Jing Li ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Deep Understanding ◽  
Magnetic Coupling ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Electronic And Magnetic Properties ◽  
Conducting Path ◽  
Magnetic Insulators ◽  
Quantum Technology

AbstractThe discovery of two-dimensional (2D) magnetism combined with van der Waals (vdW) heterostructure engineering offers unprecedented opportunities for creating artificial magnetic structures with non-trivial magnetic textures. Further progress hinges on deep understanding of electronic and magnetic properties of 2D magnets at the atomic scale. Although local electronic properties can be probed by scanning tunneling microscopy/spectroscopy (STM/STS), its application to investigate 2D magnetic insulators remains elusive due to absence of a conducting path and their extreme air sensitivity. Here we demonstrate that few-layer CrI3 (FL-CrI3) covered by graphene can be characterized electronically and magnetically via STM by exploiting the transparency of graphene to tunneling electrons. STS reveals electronic structures of FL-CrI3 including flat bands responsible for its magnetic state. AFM-to-FM transition of FL-CrI3 can be visualized through the magnetic field dependent moiré contrast in the dI/dV maps due to a change of the electronic hybridization between graphene and spin-polarised CrI3 bands with different interlayer magnetic coupling. Our findings provide a general route to probe atomic-scale electronic and magnetic properties of 2D magnetic insulators for future spintronics and quantum technology applications.

scholarly journals The crystal structure of the first ether solvate of hexaphenyldistannane [(Ph3Sn)2 • 2 THF]

2020 ◽  
Vol 43 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Jonathan O. Bauer
Keyword(s):  
Crystal Structure ◽  
Inclusion Compounds ◽  
Molecular Crystal ◽  
Structural Features ◽  
Structural Investigations ◽  
Crystal Solvates

AbstractStructural investigations of molecular crystal solvates can provide important information for the targeted crystallization of particular inclusion compounds. Here, the crystal structure of the first ether solvate of hexaphenyldistannane [(Ph3Sn)2 • 2 THF] is reported. Structural features in terms of host-guest interactions and in the context of the previously reported polymorphs and solvates of (Ph3Sn)2 are discussed.

scholarly journals Lattice disorder effect on magnetic ordering of iron arsenides

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Athena S. Sefat ◽  
Xiaoping P. Wang ◽  
Yaohua Liu ◽  
Qiang Zou ◽  
Mimgming Fu ◽  
...  
Keyword(s):  
Magnetic Coupling ◽  
Magnetic Ordering ◽  
Structural Features ◽  
Lattice Parameter ◽  
Chemical Compositions ◽  
Lattice Disorder ◽  
Local Lattice ◽  
Higher Temperature ◽  
Disordered Crystal ◽  
Planar Strain

AbstractThis study investigates magnetic ordering temperature in nano- and mesoscale structural features in an iron arsenide. Although magnetic ground states in quantum materials can be theoretically predicted from known crystal structures and chemical compositions, the ordering temperature is harder to pinpoint due to potential local lattice variations that calculations may not account for. In this work we find surprisingly that a locally disordered material can exhibit a significantly larger Néel temperature (TN) than an ordered material of precisely the same chemical stoichiometry. Here, a EuFe2As2 crystal, which is a ‘122’ parent of iron arsenide superconductors, is found through synthesis to have ordering below TN = 195 K (for the locally disordered crystal) or TN = 175 K (for the ordered crystal). In the higher TN crystals, there are shorter planar Fe-Fe bonds [2.7692(2) Å vs. 2.7745(3) Å], a randomized in-plane defect structure, and diffuse scattering along the [00 L] crystallographic direction that manifests as a rather broad specific heat peak. For the lower TN crystals, the a-lattice parameter is larger and the in-plane microscopic structure shows defect ordering along the antiphase boundaries, giving a larger TN and a higher superconducting temperature (Tc) upon the application of pressure. First-principles calculations find a strong interaction between c-axis strain and interlayer magnetic coupling, but little impact of planar strain on the magnetic order. Neutron single-crystal diffraction shows that the low-temperature magnetic phase transition due to localized Eu moments is not lattice or disorder sensitive, unlike the higher-temperature Fe sublattice ordering. This study demonstrates a higher magnetic ordering point arising from local disorder in 122.

Sign in / Sign up

Export Citation Format

Share Document