Pitfalls on evaluating pair exchange interactions for modelling molecule-based magnetism

The improvement of ferromagnetic properties is critical for the practical application of multiferroic materials, to be exact, BiFeO3 (BFO). Herein, we have investigated the evolution in the structure and morphology of Ho or/and Mn-doped thin films and the related diversification in ferromagnetic behavior. BFO, Bi0.95Ho0.05FeO3 (BHFO), BiFe0.95Mn0.05O3 (BFMO) and Bi0.95Ho0.05Fe0.95Mn0.05O3 (BHFMO) thin films are synthesized via the conventional sol-gel method. Density, size and phase structure are crucial to optimize the ferromagnetic properties. Specifically, under the applied magnetic field of 10 kOe, BHFO and BFMO thin films can produce obvious magnetic properties during magnetization and, additionally, doping with Ho and Mn (BHFMO) can achieve better magnetic properties. This enhancement is attributed to the lattice distortions caused by the ionic sizes difference between the doping agent and the host, the generation of the new exchange interactions and the inhibition of the antiferromagnetic spiral modulated spin structure. This study provides key insights of understanding the tunable ferromagnetic properties of co-doped BFO.

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Structure, Magnetic Properties and Magnetization Reversal Processes in Nanocrystalline Pr8Dy1Fe60Co7Mn6B14Zr1Ti3 Bulk Alloy

Revista de Chimie ◽

10.37358/rc.70.19.11.7707 ◽

2019 ◽

Vol 70 (11) ◽

pp. 4086-4088

Keyword(s):

Magnetic Properties ◽

Magnetization Reversal ◽

Exchange Interactions ◽

Soft Magnetic ◽

Bulk Alloy ◽

Saturation Ratio ◽

Pinning Mechanism ◽

Strong Exchange ◽

Xrd Studies ◽

Bulk Alloys

The present paper presents results concerning on structure, magnetic properties and magnetization reversal processes in the as-cast Pr8Dy1Fe60Co7Mn6B14Zr1Ti3 alloy in the form of 1 mm plate. The XRD studies revealed coexistence of three phases dominant Pr2(Fe,Co)14B and minor á-Fe and Fe3B. The remanence-to-saturation ratio Jr/Js equaled 0.66 and indicated on existence of strong exchange interactions between hard and soft magnetic phases. The analysis of Mrev vs. Mirr dependences, the pinning mechanism was detected in studied alloy. Keywords: bulk alloys, magnetic properties, magnetization reversal processes

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Magnetic properties of DyFe5−Co Al7: Suppression of exchange interactions and magnetocrystalline anisotropy by Co substitution

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2018.01.126 ◽

2018 ◽

Vol 741 ◽

pp. 715-722 ◽

Cited By ~ 1

Author(s):

D.I. Gorbunov ◽

A.V. Andreev ◽

D.S. Neznakhin ◽

M.S. Henriques ◽

J. Šebek ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetocrystalline Anisotropy ◽

Exchange Interactions ◽

Co Substitution

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First-principles studies of the elastic and magnetic properties of monolayer CrN

International Journal of Modern Physics B ◽

10.1142/s0217979221503021 ◽

2021 ◽

Author(s):

Tai Ma ◽

Jia Wang ◽

Xu Li ◽

Min Pu

Keyword(s):

Magnetic Properties ◽

Band Structure ◽

First Principles ◽

Electronic Band Structure ◽

Strain Analysis ◽

Exchange Interactions ◽

Potential Method ◽

Graphene Monolayer ◽

Electronic Band ◽

Spin Electronics

Two-dimensional (2D) materials with robust ferromagnetism properties have high potentials for application in the field of spintronics. However, extensively pursued 2D sheets, including pure graphene, monolayer BN, and layered transition metal dichalcogenides, are either nonmagnetic or weakly magnetic. The elastic, electronic and magnetic properties of monolayer CrN are calculated using the plane wave pseudo potential method based on first-principles density function theory. Upon determining through calculation that the structure of the monolayer CrN nanosheet is stable, its layer modulus [Formula: see text] shows that its strain resistance is stronger than that of graphene. Through strain analysis, materials with a monolayer CrN type of structure can be obtained. It is determined that 10% of the change in equilibrium area is still applicable to the 2D EOS, showing that this structure is quite stable. The spin-polarized electronic band structure is also calculated under different plane symmetry strains. The plane strain can be used to effectively adjust the metallic and magnetic properties of the material. Analyses of the band structure and density of states reveal that this material is half-metallic, where the origin of the ferromagnetism is related to [Formula: see text]–[Formula: see text] exchange interactions between the Cr and N atoms. Monolayer CrN has semimetallic properties and strong ferromagnetic (FM) properties. The FM effect can enhance the stability of the material. The results show that monolayer CrN is a semimetallic material with good elastic properties and a strong FM property. This material is therefore expected to have good application rospects in the field of spin electronics.

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Solvothermal Syntheses, Crystal Structures of Two New Thioantimonates(III) of the Mn2(L)Sb2S5 Family with L = Diethylenetriamine and N-Methyl-1,3-Diaminopropane and a Study of the Magnetic Properties of Four Compounds of the Series

Zeitschrift für Naturforschung B ◽

10.1515/znb-2004-0818 ◽

2004 ◽

Vol 59 (8) ◽

pp. 869-876 ◽

Cited By ~ 44

Author(s):

L. Engelke ◽

R. Stähler ◽

M. Schur ◽

C. Näther ◽

W. Bensch ◽

...

Keyword(s):

Magnetic Properties ◽

Elevated Temperatures ◽

Exchange Interactions ◽

Building Blocks ◽

Monoclinic Space Group ◽

Antiferromagnetic Materials ◽

Distorted Octahedra ◽

Secondary Building Units ◽

Low Dimensional ◽

New Compounds

AbstractThe two new compounds Mn2(L)Sb2S5 (L = diethylenetriamine = DIEN, N-methyl-1,3- diaminopropane = MDAP) were prepared under solvothermal conditions using the elements as starting materials. Both compounds crystallise in the monoclinic space group P21/c with the lattice parameters a=10.669(7), b=12.805(2), c=12.072(1)Å , β =115.786(7)°,V =1485.1(4) Å3 for L = DIEN and a = 10.1859(7), b = 12.7806(6), c = 12.1256(8)Å , β = 110.173(8)°, V = 1481.7(2) Å3 for L = MDAP and Z = 4. The primary building units are SbS3 pyramids, MnS6 and MnS4N2 distorted octahedra. These primary building blocks are interconnected to form Mn2Sb2S4 hetero-cubane units. The hetero-cubanes share common corners, edges and faces thus forming a second heterocubane. These secondary building units are joined to form layers within the (100) plane. The connection mode yields ellipsoidal pores within the layers. The amines are exclusively bound to one of the two crystallographically independent Mn2+ cations and they point into the pores and between the layers separating the layers from each other. The interlayer separation and the size of the pores depend on the sterical requirements of the amine incorporated into the network. A pronounced distortion of the MnS4N2 octahedron results from a significant elongation of one Mn-S distance from 2.866 Å (L = methylamine, MA) to 3.185 Å for L = MDAP. The magnetic susceptibility curves are typical for low-dimensional antiferromagnetic materials and the large negative values for the Weiss constant Θ indicate strong antiferromagnetic exchange interactions. The magnetic properties are significantly influenced by the change of the Mn-S bonds introduced by the different amines. The compounds decompose at elevated temperatures with a two step reaction for L = MA and ethylenediamine and in a one step reaction for the bidentate acting amine molecules.

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Impact of Alkali Ions Codoping on Magnetic Properties of La0.9A0.1Mn0.9Co0.1O3 (A: Li, K, Na) Powders and Ceramics

Applied Sciences ◽

10.3390/app10248786 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8786

Author(s):

Paweł Głuchowski ◽

Ruslan Nikonkov ◽

Robert Tomala ◽

Wiesław Stręk ◽

Tatsiana Shulha ◽

...

Keyword(s):

High Pressure ◽

Magnetic Properties ◽

Exchange Interactions ◽

Structural Disorder ◽

Subsequent Increase ◽

Cobalt Ions ◽

X Ray ◽

Alkali Ions ◽

High Pressure Sintering ◽

Combustion Technique

The aim of the work was to check how the introduction of alkali and cobalt ions into a manganese structure can affect the structural disorder and, in consequence, lead to the changes (improvements) of magnetic properties. The high-pressure sintering technique was applied to check if the external factor can modify the magnetization of manganites. Nanocrystalline La0.9A0.1Mn0.9Co0.1O3 (where A is Li, K, Na) powders were synthesized by the combustion technique. The respective powders were used for nanoceramics preparation by the high-pressure sintering technique. The structure and morphology of the compounds were studied by X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Magnetization studies for all compounds were performed in order to check the changes induced by either codoping or the sintering pressure. It was found that the type of the dopant ion and sintering pressure produced significant changes to the magnetic properties of the studied compounds. Alkali ions lead to the stabilization of Co ions in the +2 oxidation state and the formation of positive exchange interactions Mn3+–Mn4+ and Co2+–Mn4+ and the subsequent increase in remanent magnetization. High sintering pressure leads to a decrease in grain size and reduction of long-range ferromagnetic order and lower magnetization.

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