scholarly journals Magnetic structure analysis of rare earth permanent magnet Sm2Fe17N3

2014 ◽  
Vol 70 (a1) ◽  
pp. C1460-C1460 ◽  
Author(s):  
Kotaro Saito ◽  
Nobuhito Inami ◽  
Yasuo Takeichi ◽  
Tetsuro Ueno ◽  
Ryoko Sagayama ◽  
...  
Keyword(s):  
Rare Earth ◽  
Neutron Diffraction ◽  
Magnetic Structure ◽  
Structure Analysis ◽  
Permanent Magnets ◽  
Nearest Neighbor ◽  
Magnetic Moments ◽  
High Coercivity ◽  
Diffraction Measurement ◽  
Fe Sites

Rare earth intermetallic compound Sm2Fe17N3 exhibits notalble magnetic properties such as high Curie temperature and high coercivity which are very suitable for permanent magnets [1,2]. Although microscopic magnetic structure is one of the basic information for magnetic materials, there is no report about the magnetic structure of Sm2Fe17N3 for our knowledge. This is because samarium's neutron absorption cross section is huge enough to make researchers hesitate to have neutron diffraction experiments of Sm compounds. We have carried out powder neutron diffraction measurement of Sm2Fe17N3 with a straightforward solution to the problem by taking long measurement time. Synchrotron x-ray diffraction measurements with single crystal has also been done to obtain initial crystal structure parameters for magnetic structure analysis and we have succeeded to analyze the magnetic structure of Sm2Fe17N3 at room temperature. Among four Fe sites in the unit cell, while one Fe site which is the nearest neighbor of nitrogen shows smaller magnetic moment than normal iron, two Fe sites show enhancement in their magnetic moments. This phenomenon can be understood as 'cobaltization' of Fe by the adjacent nitrogen through hybridization.

scholarly journals Crystal and magnetic structures of R 2Ni1.78In compounds (R = Tb, Ho, Er and Tm)

2021 ◽  
Vol 77 (5) ◽  
pp. 824-832
Author(s):  
Stanisław Baran ◽  
Aleksandra Deptuch ◽  
Andreas Hoser ◽  
Bogusław Penc ◽  
Yuriy Tyvanchuk ◽  
...  
Keyword(s):  
Rare Earth ◽  
Neutron Diffraction ◽  
Magnetic Structure ◽  
Magnetic Moments ◽  
Symmetry Analysis ◽  
Crystalline Electric Field ◽  
Magnetic Structures ◽  
Antiferromagnetic Ordering ◽  
Crystal And Magnetic Structures ◽  
The Rare Earth

The crystal and magnetic structures in R 2Ni1.78In (R = Ho, Er and Tm) have been studied by neutron diffraction. The compounds crystallize in a tetragonal crystal structure of the Mo2FeB2 type (space group P4/mbm). At low temperatures, the magnetic moments, localized solely on the rare earth atoms, form antiferromagnetic structures described by the propagation vector k = [kx , kx , ½], with kx equal to ¼ for R = Er and Tm or 0.3074 (4) for R = Ho. The magnetic moments are parallel to the c axis for R = Ho or lie within the (001) plane for R = Er and Tm. The obtained magnetic structures are discussed on the basis of symmetry analysis. The rare earth magnetic moments, determined from neutron diffraction data collected at 1.6 K, are 6.5 (1) μB (Er) and 6.09 (4) μB (Tm), while in the incommensurate modulated magnetic structure in Ho2Ni1.78In the amplitude of modulation of the Ho magnetic moment is 7.93 (8) μB. All these values are smaller than those expected for the respective free R 3+ ions. A symmetry analysis of the magnetic structure in Tb2Ni1.78In is also included, as such information is missing from the original paper [Szytuła, Baran, Hoser, Kalychak, Penc & Tyvanchuk (2013). Acta Phys. Pol. A, 124, 994–997]. In addition, the results of magnetometric measurements are reported for Tm2Ni1.78In. The compound shows antiferromagnetic ordering below the Néel temperature of 4.5 K. Its magnetic properties are found to originate from magnetic moments localized solely on the thulium atoms (the nickel atoms remain non-magnetic in Tm2Ni1.78In). The reduction of rare earth magnetic moments in the ordered state in R 2Ni1.78In (R = Tb, Ho, Er and Tm) and the change in direction of the moments indicate the influence of the crystalline electric field (CEF) on the stability of the magnetic order in the investigated compounds.

A DETERMINATION OF THE SHEAR FORCE OF THIN HIGH-COERCIVITY PERMANENT MAGNETS MADE FROM THE ALLOY WITH RARE-EARTH ELEMENTS

2021 ◽  
pp. 24-30
Author(s):  
A. Ya. Krasilʼnikov ◽  
A. A. Krasilʼnikov
Keyword(s):  
Rare Earth ◽  
Magnetic Flux ◽  
Rare Earth Elements ◽  
Standard Method ◽  
Shear Force ◽  
Permanent Magnets ◽  
High Coercivity ◽  
Research Results ◽  
Magnetic Couplings

The article considers the possibility of using a standard method for calculating the shear force of thin, high-coercivity neodymium–iron–boron type permanent magnets in magnetic clutches (couplings). The research results allowed to introduce a correction coefficients in the method of calculating the transmitting torque in magnetic clutches (couplings) with thin magnets. The possibility of 08H22N6T brand steel using for magnetic flux conductors manufacturing in a magnetic couplings.

scholarly journals Additive manufacturing of heavy rare earth free high-coercivity permanent magnets

2020 ◽  
Vol 188 ◽  
pp. 733-739 ◽  
Author(s):  
A.S. Volegov ◽  
S.V. Andreev ◽  
N.V. Selezneva ◽  
I.A. Ryzhikhin ◽  
N.V. Kudrevatykh ◽  
...  
Keyword(s):  
Rare Earth ◽  
Additive Manufacturing ◽  
Permanent Magnets ◽  
High Coercivity ◽  
Heavy Rare Earth

Magnetic behaviour of synthetic Co2SiO4

2009 ◽  
Vol 65 (6) ◽  
pp. 664-675 ◽  
Author(s):  
Andrew Sazonov ◽  
Martin Meven ◽  
Vladimir Hutanu ◽  
Gernot Heger ◽  
Thomas Hansen ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Magnetic Structure ◽  
Magnetic Moment ◽  
Mirror Symmetry ◽  
Magnetic Moments ◽  
Exchange Interactions ◽  
Magnetic Behaviour ◽  
Relative Strength ◽  
Antiferromagnetic Ordering ◽  
Polarized Neutron

Synthetic Co2SiO4 crystallizes in the olivine structure (space group Pnma) with two crystallographically non-equivalent Co positions and shows antiferromagnetic ordering below 50 K. We have investigated the temperature variation of the Co2SiO4 magnetic structure by means of non-polarized and polarized neutron diffraction for single crystals. Measurements with non-polarized neutrons were made at 2.5 K (below T N), whereas polarized neutron diffraction experiments were carried out at 70 and 150 K (above T N) in an external magnetic field of 7 T parallel to the b axis. Additional accurate non-polarized powder diffraction studies were performed in a broad temperature range from 5 to 500 K with small temperature increments. Detailed symmetry analysis of the Co2SiO4 magnetic structure shows that it corresponds to the magnetic (Shubnikov) group Pnma, which allows the antiferromagnetic configuration (Gx , Cy , Az ) for the 4a site with inversion symmetry \bar{1} (Co1 position) and (0,Cy ,0) for the 4c site with mirror symmetry m (Co2 position). The temperature dependence of the Co1 and Co2 magnetic moments obtained from neutron diffraction experiments was fitted in a modified molecular-field model. The polarized neutron study of the magnetization induced by an applied field shows a non-negligible amount of magnetic moment on the oxygen positions, indicating a delocalization of the magnetic moment from Co towards neighbouring O owing to superexchange coupling. The relative strength of the exchange interactions is discussed based on the non-polarized and polarized neutron data.

Fracture Toughness of Samarium Cobalt Magnets

2015 ◽  
Author(s):  
Paul R. Curtin ◽  
Steve Constantinides ◽  
Patricia Iglesias Victoria
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Rare Earth ◽  
Crack Propagation ◽  
Grain Boundaries ◽  
Permanent Magnets ◽  
Raw Material ◽  
High Coercivity ◽  
Standard Material ◽  
Average Grain Size

Samarium Cobalt (SmCo) magnets have been the magnet of choice for a variety of industries for many years due to their favorable magnetic properties. Their high coercivity, combined with a low temperature coefficient, make them the ideal permanent magnet for demanding high temperature applications. One of the biggest concerns with rare earth magnets is their brittleness. Samarium Cobalt magnets in particular are prone to fracturing during machining and assembly. In manufacturing, great care must be taken to avoid chipping or fracturing these magnets due to their brittle nature. There are two main grades of Samarium Cobalt magnets, 1:5 and 2:17. These ratios define the nominal ratio of rare earth to transition metal content. In this paper, an investigation is performed on the fracture toughness of permanent magnets based on the Samarium Cobalt 2:17 composition. Various techniques are used to characterize the microstructure of the material, and quantify the material properties. Optical microscopy is used to characterize the grain structure of the material and quantify the porosity of the material after sintering. By comparing the average grain size and fracture toughness of several samples, grain size was shown to not affect fracture toughness in standard material. Latent cracks in defective material showed no preference to follow grain boundaries, oxides inclusions or voids. River marks in fracture surfaces are seen through scanning electron microscopy, confirming the transgranular cracking pattern seen by Li et al [1]This suggests that the toughness of the material is an inherent property of the main phase, not of grain boundaries or contaminants. Samarium Cobalt magnets exhibit both mechanical and magnetic anisotropy due to the alignment of their crystal structure in the manufacturing process. Using Palmqvist indentation crack techniques, the magnetic orientation of the grains was seen to greatly influence the direction of crack propagation from the tip of the indenter. Measurements of fracture toughness using this technique produce highly scattered data due to this anisotropic nature of the material. Specimens loaded with the indenter axis parallel to the direction of orientation show normal Palmqvist cracks, while specimens loaded perpendicular to the direction of magnetization exhibit crack propagation initiating from the faces of the indenter. To better quantify the material’s brittleness, fracture testing is performed on specially prepared samples to obtain an absolute measure of fracture toughness (K1c). Results show that SmCo is measurably weaker than other magnetic materials such as neodymium iron boron magnets[2]. Furthermore, neither relative concentration of Samarium nor source of raw material show notable effect on the fracture toughness of the material.

The magnetic structure of braunite Mn2+Mn3+6O8/SiO4

1998 ◽  
Vol 213 (1) ◽  
Author(s):  
S. Ohmann ◽  
I. Abs-Wurmbach ◽  
N. Stüßer ◽  
T. M. Sabine ◽  
K. Westerholt
Keyword(s):  
Neutron Diffraction ◽  
Magnetic Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
Neutron Powder Diffraction Data ◽  
Weakly Coupled

AbstractNeutron powder diffraction data of braunite MnThe magnetic structure is dominated by the magnetic ordering of the A layers thus reflecting the relations of the chemical cell: Within the (001) plane of the A sheets magnetic moments of the two nonequivalent MnMagnetization experiments indicate that besides the afordered Mn ions weakly coupled spins ordering at temperatures below 2 K exist. In accordance with that, additional neutron diffraction reflections arise at

High Coercivity Mechanism Of The Die-Upset Hard Magnets Re13.75Fe80.25B6 (Re = Nd, Pr): Possible Correlation To Specific DefectMicrostructure

1999 ◽  
Vol 5 (S2) ◽  
pp. 42-43
Author(s):  
V.V. Volkov ◽  
Y. Zhu
Keyword(s):  
Magnetic Structure ◽  
Permanent Magnets ◽  
Materials Science ◽  
High Energy ◽  
High Coercivity ◽  
Energy Product ◽  
Hard Magnets ◽  
Energy Products ◽  
Processing Techniques

The magnetic properties of permanent magnets are sensitive to their microstructure. In particular, for the family of Nd(Pr)-Fe-B magnets a very different coercivity and energy products may be obtained by several processing techniques. It was experimentally found that a small excess of Nd over the exact phase composition of Nd2Fe14B plays an important role in obtaining high-energy products during the die-upset processing of the anisotropic hard magnets. However the specific role of the Nd excess on both magnetic structure and microstructure of these die-upset magnets is unclear and controversial. Answers to these questions may help to correctly address some major issues in materials science, e.g. how microstructure is related to magnetic structure of hard magnets, and how to optimize the performance of hard magnets.In-situ TEM magnetizing experiments combined with Lorentz magnetic microscopy in Fresnel-Foucault modes were used to characterize the magnetic structure of die-upset, high energy-product hard magnets Nd13.75Fe80.25B6 and Pr13.75Fe80.25B6.

Neutron diffraction measurement and the magnetic structure of the HoNi compound

1984 ◽  
Vol 55 (6) ◽  
pp. 2031-2033 ◽  
Author(s):  
Y. Isikawa ◽  
K. Mori ◽  
K. Sato ◽  
M. Ohashi ◽  
Y. Yamaguchi
Keyword(s):  
Neutron Diffraction ◽  
Magnetic Structure ◽  
Diffraction Measurement ◽  
Neutron Diffraction Measurement
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