Intergrain exchange interaction of Pr-Fe-B composite nanocrystalline alloys

2020 ◽  
Author(s):  
V. E. Maltseva ◽  
A. S. Volegov ◽  
S. V. Andreev ◽  
A. S. Bolyachkin
2012 ◽  
Vol 190 ◽  
pp. 323-326 ◽  
Author(s):  
Dmitriy Karpenkov ◽  
Alexei Y. Karpenkov ◽  
Kostantin P. Skokov ◽  
Elena M. Semenova ◽  
Roman F. Smirnov ◽  
...  

Synthesis of nanocomposite based on binary compound and determination of dependence between the values of magnetocaloric effect (MCE) and the grain size of such specimens are the purposes of this work. The results of the investigation in microcrystalline and nanocrystalline samples Y25Fe75 and Y35Fe65 alloys show, that reduction of the grain size down to 80-100 nanometers on nanocrystalline samples of Y25Fe75 and Y35Fe65 alloys leads to increasing of value of MCE by 20-25 % from comparison with values on microcrystalline samples. It can be explained by intergrain exchange interaction in nanocrystalline alloys.


1980 ◽  
Vol 41 (C5) ◽  
pp. C5-289-C5-292 ◽  
Author(s):  
C. Lewiner ◽  
J. A. Gaj ◽  
G. Bastard

Author(s):  
О. Мирославович Карбованець ◽  
Мирослав Іванович Карбованець ◽  
Володимир Юрійович Лазур ◽  
М. В. Хома

2016 ◽  
pp. 4024-4028 ◽  
Author(s):  
Sergey I. Pokutnyi ◽  
Wlodzimierz Salejda

The possibility of occurrence of the excitonic  quasimolecule formed of spatially separated electrons and holes in a nanosystem that consists  of  CuO quantum dots synthesized in a silicate glass matrix. It is shown that the major contribution to the excitonic quasimolecule binding energy is made by the energy of the exchange interaction of electrons with holes and this contribution is much more substantial than the contribution of the energy of Coulomb interaction between the electrons and holes.


Doklady BGUIR ◽  
2020 ◽  
Vol 18 (7) ◽  
pp. 87-95
Author(s):  
M. S. Baranava ◽  
P. A. Praskurava

The search for fundamental physical laws which lead to stable high-temperature ferromagnetism is an urgent task. In addition to the already synthesized two-dimensional materials, there remains a wide list of possible structures, the stability of which is predicted theoretically. The article suggests the results of studying the electronic properties of MAX3 (M = Cr, Fe, A = Ge, Si, X = S, Se, Te) transition metals based compounds with nanostructured magnetism. The research was carried out using quantum mechanical simulation in specialized VASP software and calculations within the Heisenberg model. The ground magnetic states of twodimensional MAX3 and the corresponding energy band structures are determined. We found that among the systems under study, CrGeTe3 is a semiconductor nanosized ferromagnet. In addition, one is a semiconductor with a bandgap of 0.35 eV. Other materials are antiferromagnetic. The magnetic moment in MAX3 is localized on the transition metal atoms: in particular, the main one on the d-orbital of the transition metal atom (and only a small part on the p-orbital of the chalcogen). For CrGeTe3, the exchange interaction integral is calculated. The mechanisms of the formation of magnetic order was established. According to the obtained exchange interaction integrals, a strong ferromagnetic order is formed in the semiconductor plane. The distribution of the projection density of electronic states indicates hybridization between the d-orbital of the transition metal atom and the p-orbital of the chalcogen. The study revealed that the exchange interaction by the mechanism of superexchange is more probabilistic.


2001 ◽  
Vol 37 (4) ◽  
pp. 2229-2231 ◽  
Author(s):  
L.K. Varga ◽  
V. Franco ◽  
A. Kakay ◽  
G. Kovacs ◽  
F. Mazaleyrat

2021 ◽  
Vol 27 (S1) ◽  
pp. 2420-2424
Author(s):  
Thomas Koenig ◽  
Hongyu Wang ◽  
Kayla Cole-Piepke ◽  
Alicia Koenig ◽  
Sourav Garg ◽  
...  

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