scholarly journals Structural, Magnetic and Mössbauer Studies of Ga and Zr Doped Dy2Fe17-XZrX and Dy2Fe16Ga1-xZrx (x=0.00, 0.25, 0.50, 0.75, 1.00)

2019 ◽  
Author(s):  
Jiba Nath Dahal ◽  
K. S. Syed Ali
Keyword(s):  
Curie Temperature ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Rietveld Analysis ◽  
Unit Cell ◽  
Arc Melting ◽  
Melting Technique ◽  
Average Hyperfine Field ◽  
Crystalline System ◽  
Ga Substitution

In this article, the effect of substitution of Zr and Ga in Dy2Fe17 prepared by arc melting technique are studied. The substitution of Zr and Ga in Dy2Fe17 was found to have an important effect on their structure and magnetic properties. The Rietveld analysis conformed that the crystalline system wereTh2Ni17 structure. Lattice parameters a (Å) and c (Å), unit cell volume (Å3), bonding distance (Å) were calculated by using Rietveld analysis. The unit cell volume of Dy2Fe17-xZrx and Dy2Fe16Ga1-xZrx increase linearly with the Zr and Ga substitution. The substitution of Zr and Ga are limited up to x=1 in order to avoid the decrease in saturation magnetization. The Curie temperature (Tc) of Dy2Fe17-xZrx and Dy2Fe16Ga1-xZrx are found to be Zr content dependent. The Curie temperature is found to be increasing first and then decrease for higher Zr content. The maximum curie temperature was observed 510K at x = 0.75 for Dy2Fe17-xZrx and 505.1 K at x = 0.5 for Dy2Fe17-xZrx which are102 K and 97 K higher than Dy2Fe17. The room temperature Mössbauer analysis shows the decrease in average hyperfine field and increase in isomer shift with Zr doping.

scholarly journals Effect of Ga and Zr Substitution on the Properties of Dy2Fe17−XZrX and Dy2Fe16Ga1−xZrx (0 ≤ x ≤ 1) Intermetallic Compounds Prepared via Arc Melting Process

2020 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Jiba Nath Dahal ◽  
K.S. Syed Ali ◽  
S.R. Mishra ◽  
Dipesh Neupane
Keyword(s):  
Curie Temperature ◽  
Cell Volume ◽  
Intermetallic Compounds ◽  
Unit Cell Volume ◽  
Melting Process ◽  
Rietveld Analysis ◽  
Unit Cell ◽  
Average Hyperfine Field ◽  
Crystalline System ◽  
Ga Substitution

The effects of substitution of Zr and Ga on the structural and magnetic properties of Dy2Fe17 intermetallic compound were investigated in this study. The Rietveld analysis confirmed that the crystalline system was a Th2Ni17 structure. Lattice parameters a (Å) and c (Å), unit cell volume (Å3), and bonding distance (Å) were calculated using Rietveld analysis. The unit cell volume of Dy2Fe17−xZrx and Dy2Fe16Ga1−xZrx increased linearly with Zr and Ga substitution. The Curie temperature (Tc) of Dy2Fe17−xZrx and Dy2Fe16Ga1−xZrx was found to be Zr content-dependent. The maximum Curie temperatures were observed at 510 K (x = 0.75 Zr content) for Dy2Fe17−xZrx and 505.1 K (x = 0.5 Zr content) for Dy2Fe16Ga1−xZrx, which are 102 K and 97 K higher than the value found for Dy2Fe17, respectively. The room-temperature Mössbauer analysis showed a decrease in the average hyperfine field and increases in the isomer shift with Zr doping. The overall improvement in Curie temperature with the substitution strategy of Zr–Ga substitution in 2:17 intermetallic compounds could find potential use of these magnetic compounds in high-temperature applications.

Diffusion of Carbon into RE2Fe17(RE=RARE Earth) Lattice: A High Temperature Approach

1998 ◽  
Vol 527 ◽  
Author(s):  
M. Venkatesan ◽  
U.V. Varadaraju ◽  
K.V.S. Rama Rao
Keyword(s):  
Curie Temperature ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Uniaxial Anisotropy ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Volume Increase ◽  
Melting Technique ◽  
Interstitial Carbides ◽  
Ga Substitution

ABSTRACTThe interstitial carbides HoErFe15Ga2Cy (y=0,0.5,1.0,1.5,2.0) were synthesized by are melting technique and characterized by X-ray diffraction and magnetization measurements. The hexagonal Th2Ni17 type structure persisted in all compounds. Both the Curie temperature TC and unit cell volume v are found to increase monotonically with increasing carbon concentration. The unit cell volume increase of Ga substituted carbide HoErFe15Ga2C2.0 is around 6.1% compared to HoErFe17. The Curie temperature increase is mainly due to the strengthening of exchange interaction. The Ga substitution is found to not only help the formation of single phase but also enhance the uniaxial anisotropy.

scholarly journals Study of Structural, Magnetic, and Mossbauer Properties of Dy2Fe16Ga1−xNbx (0.0 ≤ x ≤ 1.0) Prepared via Arc Melting Process

2021 ◽  
Vol 7 (3) ◽  
pp. 42
Author(s):  
Jiba N. Dahal ◽  
Kalangala Sikkanther Syed Ali ◽  
Sanjay R. Mishra
Keyword(s):  
Isomer Shift ◽  
Cell Volume ◽  
Intermetallic Compounds ◽  
Unit Cell Volume ◽  
Rietveld Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Nb Content

Intermetallic compounds of Dy2Fe16Ga1−xNbx (x = 0.0 to 1.00) were synthesized by arc melting. Samples were investigated for structural, magnetic, and hyperfine properties using X-ray diffraction, vibration sample magnetometer, and Mossbauer spectrometer, respectively. The Rietveld analysis of room temperature X-ray diffraction data shows that all the samples were crystallized in Th2Fe17 structure. The unit cell volume of alloys increased linearly with an increase in Nb content. The maximum Curie temperature Tc ~523 K for x = 0.6 sample is higher than Tc = 153 K of Dy2Fe17. The saturation magnetization decreased linearly with increasing Nb content from 61.57 emu/g for x = 0.0 to 42.46 emu/g for x = 1.0. The Mössbauer spectra and Rietveld analysis showed a small amount of DyFe3 and NbFe2 secondary phases at x = 1.0. The hyperfine field of Dy2Fe16Ga1−xNbx decreased while the isomer shift values increased with the Nb content. The observed increase in isomer shift may have resulted from the decrease in s electron density due to the unit cell volume expansion. The substantial increase in Tc of thus prepared intermetallic compounds is expected to have implications in magnets used for high-temperature applications.

Spin Polarons at High Temperatures in Undoped Lanthanum Manganites

2010 ◽  
Vol 168-169 ◽  
pp. 473-476
Author(s):  
T.I. Arbuzova ◽  
Sergey V. Naumov ◽  
Natalia V. Kostromitina
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Cell Volume ◽  
High Temperatures ◽  
Unit Cell Volume ◽  
Paramagnetic State ◽  
Unit Cell ◽  
Temperature Range ◽  
Lanthanum Manganites ◽  
Spin Polarons

Magnetic properties of undoped samples of lanthanum manganites in the temperature range 77-650K are reported. The ferromagnetic Curie temperature increases when the unit-cell volume decreases and the number of cation defects increases. Uncorrelated polarons and noninteracting moments of Mn ions are present in the region TC < T < 440K. Above 2TC < 440 K < T, the nonstoihiometric LaMnO3 compound passes into the homogeneous paramagnetic state.

scholarly journals Allanite at high temperature: effect of REE on the thermal behaviour of epidote-group minerals

2021 ◽  
Vol 48 (9) ◽  
Author(s):  
G. Diego Gatta ◽  
Francesco Pagliaro ◽  
Paolo Lotti ◽  
Alessandro Guastoni ◽  
Laura Cañadillas-Delgado ◽  
...  
Keyword(s):  
Cell Volume ◽  
Thermal Behaviour ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Atomic Scale ◽  
Elastic Behaviour ◽  
Positive Trend ◽  
Cell Parameters ◽  
Thermal Anisotropy ◽  
Different Temperatures

AbstractThe thermal behaviour of a natural allanite-(Ce) has been investigated up to 1073 K (at room pressure) by means of in situ synchrotron powder X-ray diffraction and single-crystal neutron diffraction. Allanite preserves its crystallinity up to 1073 K. However, up to 700 K, the thermal behaviour along the three principal crystallographic axes, of the monoclinic β angle and of the unit-cell volume follow monotonically increasing trends, which are almost linear. At T > 700–800 K, a drastic change takes place: an inversion of the trend is observed along the a and b axes (more pronounced along b) and for the monoclinic β angle; in contrast, an anomalous increase of the expansion is observed along the c axis, which controls the positive trend experienced by the unit-cell volume at T > 700–800 K. Data collected back to room T, after the HT experiments, show unit-cell parameters significantly different with respect to those previously measured at 293 K: allanite responds with an ideal elastic behaviour up to 700 K, and at T > 700–800 K its behaviour deviates from the elasticity field. The thermo-elastic behaviour up to 700 K was modelled with a modified Holland–Powell EoS; for the unit-cell volume, we obtained the following parameters: VT0 = 467.33(6) Å3 and αT0(V) = 2.8(3) × 10–5 K−1. The thermal anisotropy, derived on the basis of the axial expansion along the three main crystallographic directions, is the following: αT0(a):αT0(b):αT0(c) = 1.08:1:1.36. The T-induced mechanisms, at the atomic scale, are described on the basis of the neutron structure refinements at different temperatures. Evidence of dehydroxylation effect at T ≥ 848 K are reported. A comparison between the thermal behaviour of allanite, epidote and clinozoisite is carried out.

scholarly journals Neutron diffractometer covering protein crystals with large unit cell at J-PARC

2014 ◽  
Vol 70 (a1) ◽  
pp. C1746-C1746
Author(s):  
Kazuo Kurihara ◽  
Katsuaki Tomoyori ◽  
Taro Tamada ◽  
Ryota Kuroki
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Structural Information ◽  
Unit Cell ◽  
Proton Accelerator ◽  
Neutron Guide ◽  
Time Dimension ◽  
Hydrogen Atoms ◽  
Large Unit ◽  
Large Unit Cell

The structural information of hydrogen atoms and hydration waters obtained by neutron protein crystallography is expected to contribute to elucidation of protein function and its improvement. However, many proteins, especially membrane proteins and protein complexes, have larger molecular weight and then unit cells of their crystals have larger volume, which is out of range of measurable unit cell volume for conventional diffractometers. Therefore, our group had designed the diffractometer which can cover such crystals with large unit cell volume (target lattice length: 250 Å). This diffractometer is dedicated for protein single crystals and has been proposed to be installed at J-PARC (Japan Proton Accelerator Research Complex). Larger unit cell volume causes a problem to separate spots closer to each other in spatial as well as time dimension in diffraction images. Therefore, our proposed diffractometer adopts longer camera distance (L2 = 800mm) and selects decoupled hydrogen moderator as neutron source which has shorter pulse width. Under the conditions that L1 is 33.5m, beam divergence 0.40and crystal edge size 2mm, this diffractometer is estimated to be able to resolves spots diffracted from crystals with a lattice length of 220 Å in each axis at d-space of 2.0 Å. In order to cover large neutron detecting area due to long camera distance, novel large-area detector (larger than 300mm × 300mm) with a spatial resolution of better than 2.5mm is under development. More than 40 these detectors plan to be installed, providing the total solid angle coverage of larger than 33%. For neutron guide, ellipsoidal supermirror is considered to be adopted to increase neutron flux at the sample position. The final gain factor of this diffractometer is estimated to be about 20 or larger as compared with BIX-3/4 diffractometers operated in the research reactor JRR-3 at JAEA (Japan Atomic Energy Agency) [1,2].

X-ray powder diffraction data for tetrazene nitrate monohydrate, C2H9N11O4

2021 ◽  
pp. 1-3
Author(s):  
J. Maixner ◽  
J. Ryšavý
Keyword(s):  
Cell Volume ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for tetrazene nitrate monohydrate, C2H9N11O4, are reported [a = 5.205(1) Å, b = 13.932(3) Å, c = 14.196(4) Å, β = 97.826(3)°, unit-cell volume V = 1019.8(4) Å3, Z = 4, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurities were observed.

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