Special Issue "Crystal Structure of Magnetic Materials"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystal Engineering".

Deadline for manuscript submissions: closed (1 October 2017)

Special Issue Editor

Guest Editor
Dr. Alex V. Morozkin

Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, Moscow, GSP-2, 119991, Russia
Website | E-Mail
Interests: rare earth compounds; ternary phase diagram; crystal structure; magnetic properties; magnetocaloric effect; neutron diffraction; magnetic structure

Special Issue Information

Dear Colleagues,

This Special Issue of Crystals reflects a new step in crystal chemistry that is characterized by the real development of instruments and methods for investigation and analyses.

For rare earth intermetallics/compounds, they are: (a) the development of X-ray and neutron diffractometers, X-ray EDS spectrometers, and magnetometers; and (b) the development of software/databases and methods for the analysis of their crystal structures, magnetic structures, and magnetic properties.

Rare earth intermetallics/compounds are interesting, as they exhibit unique crystal structures and show a massive coercive force and magnetocaloric properties, and they are interesting in potential applications for magnetic refrigerators and permanent magnets.

The development of instruments and methods permits to determine the specific features of phase diagram “rare earth-transition metal-p-element”, the crystal structure of rare earth compounds and their solid solutions, and magnetic structures and properties of rare earth compounds. Additionally, this permits to modify the physical properties of rare earth compounds using an optimal method, obtaining, e.g., giant magnetocaloric effects and coercive fields. This Special Issue should reflect this.

Dr. Alex V. Morozkin
Guest Editor

Manuscript Submission Information

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Keywords

  • Rare earth compounds
  • Ternary phase diagram
  • Crystal structure
  • Magnetic properties

Published Papers (4 papers)

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Research

Open AccessArticle First-Principles Investigations of the Structural, Anisotropic Mechanical, Thermodynamic and Electronic Properties of the AlNi2Ti Compound
Crystals 2018, 8(2), 93; https://doi.org/10.3390/cryst8020093
Received: 26 December 2017 / Revised: 4 February 2018 / Accepted: 8 February 2018 / Published: 11 February 2018
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Abstract
In this paper, the electronic, mechanical and thermodynamic properties of AlNi2Ti are studied by first-principles calculations in order to reveal the influence of AlNi2Ti as an interfacial phase on ZTA (zirconia toughened alumina)/Fe. The results show that AlNi2
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In this paper, the electronic, mechanical and thermodynamic properties of AlNi2Ti are studied by first-principles calculations in order to reveal the influence of AlNi2Ti as an interfacial phase on ZTA (zirconia toughened alumina)/Fe. The results show that AlNi2Ti has relatively high mechanical properties, which will benefit the impact or wear resistance of the ZTA/Fe composite. The values of bulk, shear and Young’s modulus are 164.2, 63.2 and 168.1 GPa respectively, and the hardness of AlNi2Ti (4.4 GPa) is comparable to common ferrous materials. The intrinsic ductile nature and strong metallic bonding character of AlNi2Ti are confirmed by B/G and Poisson’s ratio. AlNi2Ti shows isotropy bulk modulus and anisotropic elasticity in different crystallographic directions. At room temperature, the linear thermal expansion coefficient (LTEC) of AlNi2Ti estimated by quasi-harmonic approximation (QHA) based on Debye model is 10.6 × 10−6 K−1, close to LTECs of zirconia toughened alumina and iron. Therefore, the thermal matching of ZTA/Fe composite with AlNi2Ti interfacial phase can be improved. Other thermodynamic properties including Debye temperature, sound velocity, thermal conductivity and heat capacity, as well as electronic properties, are also calculated. Full article
(This article belongs to the Special Issue Crystal Structure of Magnetic Materials)
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Graphical abstract

Open AccessArticle Effect of Sonication Output Power on the Crystal Structure and Magnetism of SrFe12O19 Nanoparticles
Crystals 2018, 8(1), 45; https://doi.org/10.3390/cryst8010045
Received: 24 November 2017 / Revised: 17 December 2017 / Accepted: 16 January 2018 / Published: 19 January 2018
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Abstract
We reported the effect of the sonication output power (SOP), from 120, 180, to 240 W, on the crystal structure, morphology, and magnetic properties of SrFe12O19 nanoparticles synthesized by sonochemical process assisted with heat treatment. X-ray Diffraction analysis of the
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We reported the effect of the sonication output power (SOP), from 120, 180, to 240 W, on the crystal structure, morphology, and magnetic properties of SrFe12O19 nanoparticles synthesized by sonochemical process assisted with heat treatment. X-ray Diffraction analysis of the obtained powder showed the formation of Fe3O4 with low crystallinity degree, which increased with the increase in SOP, together in a crystalline phase identified as SrCO3. The formation of SrFe12O19 started at 1073 K, and was completed at 1173 K. However, hexaferrite was obtained with the secondary phases α-Fe2O3 and SrFeO2.5. At 1323 K, the secondary phases vanished, and a single phase SrFe12O19 was detected. Vibrating Sample Magnetometry analysis showed that the SrFeO2.5 phase caused the formation of a hysteresis loop known as the Perminvar magnetic hysteresis loop. At 1323 K, the powder synthesized at 120 W showed a specific magnetization of 67.15 Am2/kg at 1.43 × 106 A/m, and coercivity of 4.69 × 104 A/m, with a spherical-like morphology and average particle size of 56.81 nm obtained by Scanning Electron Microscopy analysis. The increment of SOP promoted a high degree of crystallinity and decrease in crystal size. Additionally, it promoted the formation of secondary phases, induced agglomeration, and modified the morphology of the particles. Full article
(This article belongs to the Special Issue Crystal Structure of Magnetic Materials)
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Open AccessArticle Impact of Annealing Temperature on the Physical Properties of the Lanthanum Deficiency Manganites
Crystals 2017, 7(10), 301; https://doi.org/10.3390/cryst7100301
Received: 20 August 2017 / Revised: 22 September 2017 / Accepted: 2 October 2017 / Published: 5 October 2017
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Abstract
The lanthanum deficiency manganites La0.8-x□xCa0.2MnO3 (x = 0, 0.1 and 0.2), where □ is a lanthanum vacancy, were prepared using the classic ceramic methods with different thermal treatments (1373 K and 973 K).
[...] Read more.
The lanthanum deficiency manganites La0.8-x□xCa0.2MnO3 (x = 0, 0.1 and 0.2), where □ is a lanthanum vacancy, were prepared using the classic ceramic methods with different thermal treatments (1373 K and 973 K). The structural, magnetic, and magnetocaloric properties of these compounds were studied as a function of annealing temperature. It was noted that the annealing temperature did not affect the crystal structure of our samples (orthorhombic structure with Pnma space group). Nevertheless, a change in the variation of the unit cell volume V, the average bond length dMn–O, and the average bond angles θMn–O–Mn were observed. Magnetization versus temperature study has shown that all samples exhibited a magnetic transition from ferromagnetic (FM) to paramagnetic (PM) phase with increasing temperature. However, it can be clearly seen that the annealing at 973 K induced an increase of the magnetization. In addition, the magnetocaloric effect (MCE) as well as the relative cooling power (RCP) were estimated. As an important result, the values of MCE and RCP in our Lanthanum-deficiency manganites are reported to be near to those found in gadolinium, considered as magnetocaloric reference material. Full article
(This article belongs to the Special Issue Crystal Structure of Magnetic Materials)
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Open AccessArticle Effect of Al Substitution on Structural, Magnetic, and Magnetocaloric Properties of Er6Fe23−xAlx (x = 0 and 3) Intermetallic Compounds
Crystals 2017, 7(6), 156; https://doi.org/10.3390/cryst7060156
Received: 16 April 2017 / Revised: 9 May 2017 / Accepted: 13 May 2017 / Published: 27 May 2017
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Abstract
The structural, magnetic, and magnetocaloric properties of Er6Fe23−xAlx (x = 0 and 3) intermetallic compounds have been studied systematically. Samples were prepared using the arc furnace by annealing at 1073 K for one week. Rietveld analysis of XRD
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The structural, magnetic, and magnetocaloric properties of Er6Fe23−xAlx (x = 0 and 3) intermetallic compounds have been studied systematically. Samples were prepared using the arc furnace by annealing at 1073 K for one week. Rietveld analysis of XRD shows the formation of pure crystalline phase with cubic Fm-3m structure. Refinement results show that the unit cell volume decreases with increasing Al content. The Curie temperature Tc of the prepared samples was found to be strongly dependent on the aluminum content. This reduces magnetization and the ferrimagnetic phase transition temperature (Tc) from 481 K (for x = 0) to 380 K (for x = 3), is due to the substitution of magnetic element (Fe) by non-magnetic atoms (Al). With the increase of the Al content, a decrease in the values of magnetic entropy is observed. The magnitude of the isothermal magnetic entropy (|∆SM|) at the Tc decreases from 1.8 J/kg·K for x = 0 to 0.58 J/kg·K for x = 3 for a field change 14 kOe. Respectively, the relative cooling power (RCP) decreases with increasing Al content reaching 42 Jkg−1 for x = 0 to 28 Jkg−1 for x = 3. Full article
(This article belongs to the Special Issue Crystal Structure of Magnetic Materials)
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