scholarly journals Magnetic properties of the low-dimensional spin-12magnetα-Cu2As2O7

2011 ◽  
Vol 84 (13) ◽  
Author(s):  
Y. C. Arango ◽  
E. Vavilova ◽  
M. Abdel-Hafiez ◽  
O. Janson ◽  
A. A. Tsirlin ◽  
...  
2009 ◽  
pp. 9418 ◽  
Author(s):  
Daopeng Zhang ◽  
Hailong Wang ◽  
Yuting Chen ◽  
Lifang Zhang ◽  
Laijin Tian ◽  
...  

2004 ◽  
Vol 59 (8) ◽  
pp. 869-876 ◽  
Author(s):  
L. Engelke ◽  
R. Stähler ◽  
M. Schur ◽  
C. Näther ◽  
W. Bensch ◽  
...  

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.


2020 ◽  
Vol 34 (18) ◽  
pp. 2050168
Author(s):  
Fei Feng ◽  
Fengdong Lv ◽  
Gongping Zheng ◽  
Guangtao Wang

We used the first principle of density functional theory to perform detailed calculations regarding the structure, and the electronic and magnetic properties of MX (M[Formula: see text]=[Formula: see text]Ga, In; X[Formula: see text]=[Formula: see text]S, Se, Te) nanoribbons. The armchair nanoribbons (ARNs) are nonmagnetic semiconductors, which have even or odd oscillations of bandgaps. All small-sized zigzag nanoribbons (ZRNs) were found to break the six-membered ring structure and move to the center, thereby exhibiting nonmagnetic semiconductor behavior owing to the quantum confinement effect. However, among the large ZRNs, which are all metals, MTe ZRNs are nonmagnetic; this differs from the case of graphene, MoS2 and Ti2CO2 nanoribbons. MX (M[Formula: see text]=[Formula: see text]Ga, In; X[Formula: see text]=[Formula: see text]S, Se) ZRNs exhibited ferromagnetism owing to the presence of the unpaired electrons on the metal-edge side and the magnetic moment of each pair of molecules, which was controlled by the size of the nanoribbons. The results provided a theoretical reference that can be used in the future to produce MX materials for application in low-dimensional semiconductor devices, spin electron transport devices and new magnetoresistance devices.


2017 ◽  
Vol 95 (2) ◽  
Author(s):  
M. L. Hneda ◽  
J. B. M. da Cunha ◽  
M. A. Gusmão ◽  
S. R. Oliveira Neto ◽  
J. Rodríguez-Carvajal ◽  
...  

2020 ◽  
Vol 75 (1-2) ◽  
pp. 191-199
Author(s):  
Aleksandr M. Golubev ◽  
Eva Brücher ◽  
Armin Schulz ◽  
Reinhard K. Kremer ◽  
Robert Glaum

AbstractPolycrystalline samples of La- and Lu-agardite with the composition RECu6(OH)6(AsO4)3 · n H2O (RE = La, Lu; n≈3) have been prepared and the structure of the products was determined by X-ray powder diffraction studies. The characterization has been complemented by Raman and UV/Vis spectroscopic, magnetic and TGA investigations. DFT calculations support the conclusions drawn from the experiments. The arsenates RECu6(OH)6(AsO4)3 · n H2O (RE = La, Lu; n≈3) are isostructural with the mineral mixite and crystallize with a hexagonal structure which contains ribbons of edge-sharing [CuO5] square-pyramids extending along the hexagonal axis. They are interconnected via (AsO4)3− groups to form hexagonal tubes of about 10 Å inner diameter. Such zeolite-like tubes host water molecules, which can be reversibly removed at moderate temperatures (T≈100°C). Like in mixite and YCu6(OH)6(AsO4)3 · 3 H2O, the Cu2+ cations in RECu6(OH)6(AsO4)3 · n H2O (RE = La, Lu; n≈3) exhibit low-dimensional antiferromagnetic properties, which are subject to changes in the Cu–O–Cu bond lengths and angles due to the lanthanide contraction.


2015 ◽  
Vol 71 (a1) ◽  
pp. s98-s98
Author(s):  
Gwilherm Nenert ◽  
O. Fabelo ◽  
K. Forsberg ◽  
C. V. Colin ◽  
J. Rodriguez-Carvajal

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