scholarly journals Features of the structural and magnetic properties of Pb(TixZr1–xO3)-NiFe1.98Co0.02O4 in the polarized state

Nukleonika ◽  
2017 ◽  
Vol 62 (2) ◽  
pp. 91-94
Author(s):  
Vadim Baev ◽  
Mieczysław Budzyński ◽  
Vladimir Laletin ◽  
Victor Mitsiuk ◽  
Natali Poddubnaya ◽  
...  

Abstract Composites with a 90%Pb(TixZr1-xO3)-10%NiFe1.98Co0.02O4 composition have been synthesized. It has been established that the polarization of samples resulting from exposure to an electric field for 1 hour of 4 kV/mm in strength at a temperature of 400 K leads to crystal structure deformation. The compression of elementary crystal cells in some areas during polarization of the sample creates conditions suitable for the enhancement of magnetic exchange interactions. It has been found that the polarization process of such compositions leads to increases in specific magnetization and magnetic susceptibility. The analysis of Mössbauer spectra has shown that the polarization of the 90%Pb(TixZr1-xO3)-10%NiFe1.98Co0.02O4 composite leads to significant changes in the effective magnetic fields of iron subspectra in various positions.

2011 ◽  
Vol 1296 ◽  
Author(s):  
Peter Entel ◽  
Denis Comtesse ◽  
Heike C. Herper ◽  
Markus E. Gruner ◽  
Mario Siewert ◽  
...  

ABSTRACTNew methods in steel design and basic understanding of the novel materials require large scale ab initio calculations of ground state and finite temperature properties of transition metal alloys. In this contribution we present ab initio modeling of the structural and magnetic properties of XYZ compounds and alloys where X, Y = Mn, Fe, Co Ni and Z = C, Si with emphasis on the Fe-Mn steels. The optimization of structural and magnetic properties is performed by using different simulation tools. In particular, the finite-temperature magnetic properties are simulated using a Heisenberg model with magnetic exchange interactions from first-principles calculations. Part of the calculations are extended to the nanoparticle range showing how ferromagnetic and antiferromagnetic trends influence the nucleation, morphologies and growth of Fe-Mn-based nanoparticles.


2004 ◽  
Vol 848 ◽  
Author(s):  
Andriy V. Tkachuk ◽  
Shane J. Crerar ◽  
Xing Wu ◽  
Craig P. T. Muirhead ◽  
Laura Deakin ◽  
...  

ABSTRACTTernary rare-earth transition-metal antimonides RExMySbz have provided fertile ground for discovering materials with varied electrical and magnetic properties such as superconductivity and ferromagnetism. The properties of two important classes of these compounds, RE3TiSb5 and RECrSb3, have been previously investigated. These studies have now been extended to RE3MSb5 (M = Zr, Hf), which show anomalies in their resistivity curves suggestive of electronic transitions, and YbCrSb3, which undergoes long-range magnetic ordering at 285 K, the highest Tc observed so far of all RECrSb3 members. Strong magnetic exchange interactions develop through coupling of f and d electrons in these compounds. The substitution of uranium for rare earth in RE3MSb5 results in the compounds U3MSb5 (M = Zr, Hf, Nb), which also display prominent transitions in their electrical resistivity and magnetic susceptibility curves.


2005 ◽  
Vol 44 (19) ◽  
pp. 6632-6640 ◽  
Author(s):  
Alexei A. Belik ◽  
Masaki Azuma ◽  
Akira Matsuo ◽  
Myung-Hwan Whangbo ◽  
Hyun-Joo Koo ◽  
...  

2000 ◽  
Vol 77 (9) ◽  
pp. 731-736
Author(s):  
H Atmani ◽  
S Grognet ◽  
J Teillet ◽  
K Zellama ◽  
R Zuberek

Nitriding thermochemical treatment under suitable parameters is used to nano-crystallize Fe73.5Cu1Nb3Si13.5B9 ribbon. This new kind of treatment leads to finer nano-structure and modifies the structural parameters of the α-Fe(Si) phase, obtained during the treatment. The magnetic properties are also improved; specific magnetization at room temperature and Curie temperature of the crystalline phase increase, and the magnetostriction constant becomes smaller. The nitrogenation seems to offer a new way to obtain nanostructured ribbons. PACS No.: 75.70


2002 ◽  
Vol 57 (10) ◽  
pp. 1129-1132 ◽  
Author(s):  
A. Elmali ◽  
Y. Elerman ◽  
I. Svoboda

The mixed-ligand dinuclear complex (2,2'-dipyridyl)-(2-acetylphenolato)copper(II) perchlorate was synthesized and its crystal structures determined. The structure consists of a dimeric unit involving a planar Cu2O2 group. The coordination sphere of the Cu atom can be described as an alongated octahedron where the basal plane is formed by the two N atoms of the 2,2'-dipyridyl molecule and the two O atoms of the acetophenon anion. Two apical Cu - O contacts complete the 4+2 coordination of the Cu atoms. They correspond to one of the O atoms of the perchlorate anion and to the O atom of the second unit. Magnetic susceptibility data obey the Curie-Weiss law with θ = -8.1(2) K. The decreasing of the effective magnetic moment from 1.94(8) μB at 300 K to 1.86(8) μB at 70 K and the negative Weiss constant indicate weak antiferromagnetic interactions between the two copper atoms in the dimeric units.


Author(s):  
Olga Yakubovich ◽  
Larisa Shvanskaya ◽  
Zlata Pchelkina ◽  
Olga Dimitrova ◽  
Anatoliy Volkov ◽  
...  

Potassium dimanganese trivanadate, KMn2V3O10, was synthesized hydrothermally and its crystal structure was determined from single-crystal X-ray diffraction data. The novel phase crystallizes with triclinic symmetry in space group P\bar 1 with unit-cell parameters of a = 6.912 (5), b = 6.993 (5), c = 9.656 (5) Å, α = 101.858 (5), β = 102.627 (5), γ = 100.669 (5)°, Z = 2 and V = 432.6 (5) Å3. Its structure is built from tetramers of MnO6 octahedra sharing edges and trimers of VO4 tetrahedra sharing vertices. These main structural fragments are linked in a three-dimensional framework with channels occupied by potassium ions. The transformation of this structure to that of interconnected NaCa3Mn(V3O10)(V2O7) is discussed. The title compound orders antiferromagnetically at T N = 8.2 K due to the magnetic exchange interactions between tetramers of Mn octahedra through VO4 tetrahedra. First-principles calculations show the magnetic couplings via Mn—O—Mn and Mn—O—V—O—Mn pathways.


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