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

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.

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Neutrons Not Entitled to Retire at the Age of 60: More than Ever Needed to Reveal Magnetic Structures

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.170.263 ◽

2011 ◽

Vol 170 ◽

pp. 263-269 ◽

Cited By ~ 46

Author(s):

Clemens Ritter

Keyword(s):

Rare Earth ◽

Giant Magnetoresistance ◽

High Temperature Superconductivity ◽

Functional Materials ◽

Symmetry Analysis ◽

Magnetic Shape Memory ◽

Magnetic Structures ◽

Magnetic Symmetry ◽

The Rare Earth

In 1949 Shull et al. [1] used for the first time neutrons for the determination of a magnetic structure. Ever since, the need for neutrons for the study of magnetism has increased. Two main reasons can be brought forward to explain this ongoing success: First of all a strong rise in research on functional materials (founding obliges) and secondly the increasing availability of easy to use programmes for the treatment of magnetic neutron diffraction data. The giant magnetoresistance effect, multiferroic materials, magnetoelasticity, magnetic shape memory alloys, magnetocaloric materials, high temperature superconductivity or spin polarized half metals: The last 15 years have seen the event of all these “hot topics” where the knowledge of the magnetism is a prerequisite for understanding the underlying functional mechanisms. Refinement programs like FULLPROF or GSAS and programs for magnetic symmetry analysis like BASIREPS or SARAH make the determination of magnetic structures accessible for non specialists. Following a historical overview on the use of neutron powder diffraction for the determination of magnetic structures, I will try to convince you of the easiness of using magnetic symmetry analysis for the determination of magnetic structures using some recent examples of own research on the rare earth iron borate TbFe3(BO3)4 and the rare earth transition metal telluride Ho6FeTe2.

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Magnetic structure analysis of rare earth permanent magnet Sm2Fe17N3

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314085398 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1460-C1460 ◽

Cited By ~ 1

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.

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Magnetic behaviour of synthetic Co2SiO4

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768109042499 ◽

2009 ◽

Vol 65 (6) ◽

pp. 664-675 ◽

Cited By ~ 11

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.

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The Magnetic Structure of the Rare-Earth Intermetallic Compound La3Co29Si4B10

MRS Proceedings ◽

10.1557/proc-804-jj3.4 ◽

2003 ◽

Vol 804 ◽

Cited By ~ 2

Author(s):

Heng Zhang ◽

M. Hofmann ◽

S. J. Kennedy ◽

S. J. Campbell

Keyword(s):

Rare Earth ◽

Intermetallic Compound ◽

Neutron Diffraction ◽

Magnetic Scattering ◽

Rietveld Refinements ◽

Magnetic Structures ◽

The Mean ◽

Diffraction Patterns ◽

Crystal And Magnetic Structures ◽

Rare Earth Intermetallic

ABSTRACTA quaternary rare-earth intermetallic compound La3Co29Si4B10 has been synthesized and the crystal and magnetic structures investigated by neutron diffraction over the temperature range 7–300 K. Rietveld refinements of the neutron diffraction patterns demonstrate that La3Co29Si4B10 is tetragonal and isostructural with Nd3Ni29Si4B10. The magnetic scattering indicates that the moments of the Co sublattice are collinear and lie in the basal plane. The mean magnetic moment for the Co atoms is μ ∼ 0.5 μB, or 13.6μB/F.U., in agreement with magnetization measurements.

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Sixty Five Years of Magnetic Structures. Present and Future of Magnetic Crystallography

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314099756 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C24-C24

Author(s):

Juan Rodriguez-Carvajal

Keyword(s):

Neutron Diffraction ◽

Magnetic Structure ◽

Magnetic Moments ◽

Spatial Arrangement ◽

Physical Review ◽

Three Dimensions ◽

Magnetic Structures ◽

Symmetry Properties ◽

Special Cases

Magnetic Crystallography is a sub-field of Crystallography concerned with the description and determination of the magnetisation density in solids. A magnetic structure corresponds to a particular spatial arrangement of magnetic moments that sets up below the ordering temperature. The determination of magnetic structures is mainly done using neutron diffraction (powder and single crystals) and in special cases the use of polarized neutrons is necessary to solve ambiguities found in the interpretation of magnetic neutron diffraction data. We can consider that Magnetic Crystallography starts with the seminal paper by C.G. Shull and S. Smart on the magnetic structure of MnO published the 29 August 1949 in the Physical Review 76, 1256. The symmetry properties of periodic arrangement of atoms are well described by the 230 space group types in three dimensions, however more complex spatial arrangements of atoms may need to be described by periodicity in higher dimensions. Incommensurate, composite and quasi-crystal structures represent a relatively small part of the huge amount of materials that can be described by conventional Crystallography, however many magnetic structures are non-commensurate: the periodicity of the orientation of the magnetic moments is not commensurate with the underlying crystal structure. The symmetry properties of magnetic structures are traditionally described using two different approaches: the magnetic Shubnikov groups [1] and the group representation analysis [2-3]. In this talk we shall describe how these approaches have been established historically and the advantages of the new trend towards the use of magnetic superspace groups. A review of the most important papers and milestones in magnetic neutron scattering as well as in the symmetry concepts will be presented. The current analytical tools and methods for determining magnetic structures and their symmetry will briefly be described.

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Symmetry analysis of complex magnetic structure in monoclinically distorted Er3Cu4Sn4

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s205252062100127x ◽

2021 ◽

Vol 77 (2) ◽

pp. 219-224

Author(s):

Stanisław Baran ◽

Aleksandra Deptuch ◽

Bogusław Penc ◽

Andreas Hoser ◽

Andrzej Szytuła

Keyword(s):

Crystal Structure ◽

High Resolution ◽

Neutron Diffraction ◽

Magnetic Structure ◽

Low Temperatures ◽

Magnetic Moments ◽

Symmetry Analysis ◽

Monoclinic Space Group ◽

Modulated Structure ◽

Powder Neutron Diffraction

The magnetic structure in Er3Cu4Sn4 has been determined using high-resolution powder neutron diffraction, supported by symmetry analysis. At low temperatures, Er3Cu4Sn4 assumes a crystal structure of the Tm3Cu4Sn4 type (in the monoclinic space group C2/m). The Er atoms occupy two distinct Wyckoff sites: 2c and 4i. It has been found that the Er magnetic moments on the 2c site form a commensurate antiferromagnetic structure (k 1 = [0, 0, ½]) below 6 K. The magnetic moments reach 8.91 (8) μB at 1.4 K and are parallel to the b axis. The Er magnetic moments on the 4i site order below 2 K and form an incommensurate antiferromagnetic sine-modulated structure (k 2 = [1, 0.4667 (1), ½]), with magnetic moments lying in the ac plane and perpendicular to the a axis. The amplitude of modulation equals 8.7 (1) μB at 1.4 K.

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Magnetic structure of TbBaCo2O5.4 perovskite

Journal of Materials Research ◽

10.1557/jmr.2002.0122 ◽

2002 ◽

Vol 17 (4) ◽

pp. 838-843 ◽

Cited By ~ 20

Author(s):

D. D. Khalyavin ◽

I. O. Troyanchuk ◽

N. V. Kasper ◽

Q. Huang ◽

J. W. Lynn ◽

...

Keyword(s):

Neutron Diffraction ◽

Diffraction Study ◽

Wide Temperature Range ◽

Spontaneous Magnetization ◽

Magnetic Moments ◽

Neutron Diffraction Study ◽

Spin Reorientation ◽

Magnetic Structures ◽

Reorientation Process ◽

Crystal And Magnetic Structures

In accordance with magnetization studies, the fast-cooled TbBaCo2O5.4 is characterized by spontaneous magnetization around 0.18 μB per cobalt ion, which develops below TN = 245 K. The neutron diffraction study of this compound revealed that magnetic moments of Co3+; ions adopting intermediate spine state are ordered antiferromagnetically. Both magnetization and neutron diffraction study showed that there is a spin reorientation process in the wide temperature range. The crystal and magnetic structures are discussed.

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Study on the crystal and magnetic structures of and by powder neutron diffraction

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/10/50/009 ◽

1998 ◽

Vol 10 (50) ◽

pp. 11703-11712 ◽

Cited By ~ 22

Author(s):

Keitaro Tezuka ◽

Yukio Hinatsu ◽

Yutaka Shimojo ◽

Yukio Morii

Keyword(s):

Neutron Diffraction ◽

Magnetic Structures ◽

Powder Neutron Diffraction ◽

Crystal And Magnetic Structures

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Neutron Scattering for Materials Science

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.112.39 ◽

2006 ◽

Vol 112 ◽

pp. 39-60 ◽

Cited By ~ 3

Author(s):

A. Szytuła

Keyword(s):

Neutron Diffraction ◽

Chemical Reactions ◽

Small Angle ◽

Materials Science ◽

Review Paper ◽

Condensed Matter ◽

Practical Applications ◽

Magnetic Structures ◽

Angle Scattering ◽

Crystal And Magnetic Structures

The work is a review paper concerning application of neutron diffraction methods for condensed matter investigations and for characterizing modern materials, namely for crystal and magnetic structures determination, small-angle scattering, investigations of chemical reactions and some practical applications. It addresses briefly a few of more prominent techniques that are important for materials scientists. In the first part of the work information on the methods and ways of interpretation of obtained results is given. Then the results for some chosen compounds are presented.

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