Observation of short range order driven large refrigerant capacity in chemically disordered single phase compound Dy2Ni0.87Si2.95

2018 ◽  
Vol 20 (19) ◽  
pp. 13580-13587 ◽  
Author(s):  
Santanu Pakhira ◽  
Chandan Mazumdar ◽  
Dibyasree Choudhury ◽  
R. Ranganathan ◽  
S. Giri
Keyword(s):  
Crystal Structure ◽  
Intermetallic Compound ◽  
Magnetocaloric Effect ◽  
Short Range ◽  
Short Range Order ◽  
Single Phase ◽  
Range Order ◽  
Refrigerant Capacity ◽  
Phase Compound ◽  
Defect Crystal

The synthesis of a new intermetallic compound Dy2Ni0.87Si2.95 is reported in defect crystal structure. The compound exhibits cluster glass behaviour with large magnetocaloric effect.

The crystal structure of orlovite, KLi2 Ti(Si4 O10)(OF): the first example of the short-range order of Ti in true trioctahedral micas

2018 ◽  
Vol 30 (2) ◽  
pp. 399-402
Author(s):  
Elena Sokolova ◽  
Frank C. Hawthorne ◽  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Vladimir Yu. Karpenko
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order

Diffuse scattering and short-range order in uranium iodine phthalocyanine [U1−x Pc2]I2−y and the X-ray structure analysis of crystals with diffuse superstructure reflections

2003 ◽  
Vol 59 (3) ◽  
pp. 384-392 ◽  
Author(s):  
J. Krawczyk ◽  
A. Pietraszko ◽  
R. Kubiak ◽  
K. Łukaszewicz
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Diffuse Scattering ◽  
Short Range ◽  
Short Range Order ◽  
Crystal Structure Analysis ◽  
Range Order ◽  
Small Range ◽  
X Ray ◽  
Unit Cells

Crystals of uranium iodine phthalocyanine present an example of a disordered commensurate modulated structure of the intergrowth type. The short-range order of both uranium ions and iodine chains [I_3^-] n has been analysed by Reverse Monte Carlo (RMC) simulation of X-ray diffuse scattering. The diffraction pattern of uranium iodine phthalocyanine contains diffuse superstructure reflections. In the routine crystal structure analysis diffuse superstructure reflections may be either omitted or measured and classified along with other Bragg reflections. The crystal structure of uranium iodine phthalocyanine is an example of such ambiguity. The crystal structures of two specimens of [U1−x Pc2]I2−y with slightly different composition have been published in the literature with different space groups and unit cells. We have shown that the structure of both specimens differs only in the degree of short-range order and is isostructural with [YbPc2]I2. We have also shown that while the omission of diffuse reflections results in the average crystal structure, the treatment of these reflections as normal Bragg reflections is incorrect and produces the structure averaged over a limited small range.

MAGNETOCALORIC EFFECT IN THE INTERMETALLIC COMPOUND Gd3Ni8Al

2012 ◽  
Vol 26 (25) ◽  
pp. 1250167 ◽  
Author(s):  
M. X. WANG ◽  
H. FU ◽  
Q. ZHENG ◽  
J. TANG
Keyword(s):  
Intermetallic Compound ◽  
Magnetocaloric Effect ◽  
Single Phase ◽  
Magnetic Entropy Change ◽  
Magnetic Measurements ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Refrigerant Capacity

The magnetic properties and magnetocaloric effect of the polycrystalline Gd 3 Ni 8 Al intermetallic compound are studied in this paper. Powder X-ray diffraction shows that the alloy is CeNi 3-type single-phase structure. The magnetic measurements indicate that the compound is ferromagnetic and undergoes a second-order phase transition at 62 K. The maximum of magnetic entropy change reaches 11 J/kg K for the field change from 0 to 50 kOe and the refrigerant capacity of the titled compound is found to be 4.8×102 J/kg.

Crystal Structure of Cu2Gd2/3S2: Interlayer Short-Range Order of Gd Vacancies

2000 ◽  
Vol 152 (2) ◽  
pp. 332-339 ◽  
Author(s):  
Mitsuko Onoda ◽  
Xue-an Chen ◽  
Akira Sato ◽  
Hiroaki Wada
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order

Short-range order of undercooled melts of PdZr 2 intermetallic compound studied by X-ray and neutron scattering experiments

2013 ◽  
Vol 102 (3) ◽  
pp. 36001 ◽  
Author(s):  
S. Klein ◽  
D. Holland-Moritz ◽  
D. M. Herlach ◽  
N. A. Mauro ◽  
K. F. Kelton
Keyword(s):  
Intermetallic Compound ◽  
Neutron Scattering ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
X Ray ◽  
Undercooled Melts

scholarly journals Crystal Structure of Cobalt Oxide Superconductors and Their Short-Range-Order Stacking

2011 ◽  
Vol 53 (6) ◽  
pp. 409-415
Author(s):  
Mitsuko ONODA ◽  
Kazunori TAKADA ◽  
Takayoshi SASAKI
Keyword(s):  
Crystal Structure ◽  
Cobalt Oxide ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Oxide Superconductors

The crystal structure of orlovite, KLi2Ti(Si4O10)(OF): the first example of the short-range order of Ti in true trioctahedral micas

2018 ◽  
Vol 30 (2) ◽  
pp. 399-402 ◽  
Author(s):  
Elena Sokolova ◽  
Frank C. Hawthorne ◽  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Vladimir Yu. Karpenko
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order

The Crystal Structure of Polylithionite-1M from Darai-Pioz, Tajikistan: the Role of Short-range Order in Driving Symmetry Reduction in 1M Li-rich Mica

2019 ◽  
Vol 57 (4) ◽  
pp. 519-528 ◽  
Author(s):  
Frank C. Hawthorne ◽  
Elena Sokolova ◽  
Atali A. Agakhanov ◽  
Leonid A. Pautov ◽  
Vladimir Yu. Karpenko
Keyword(s):  
Crystal Structure ◽  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Bond Valence ◽  
Range Order ◽  
Sum Rule ◽  
Space Group ◽  
Bond Valence Sum

Abstract The crystal structure of polylithionite-1M from Darai-Pioz, (K0.97Na0.03Rb0.01)Σ1.01(Li2.04Al0.84 Ti4+0.09Fe3+0.03)Σ3.00(Si3.98Al0.02)O10[F1.68(OH)0.33]Σ2, a 5.1974(4), b 8.9753(6), c 10.0556(7) Å, β 100.454(1)°, V 461.30(6) Å3, space group C2, Z = 2, was refined to R1 = 1.99% using MoKα X-radiation. In the space group C2, there are three octahedrally coordinated M sites in the 1M mica structure: the M(1) site is occupied by Li+ and minor vacancy that is likely locally associated with Ti4+ at the M(2) site; the M(2) site is occupied dominantly by Al3+, with other minor divalent to tetravalent cations; the M(3) site is completely occupied by Li+. In the space group C2, the structure is completely ordered. Each non-bridging O2– ion is surrounded by an ordered arrangement of 2Li+ + Al3+ + Si4+ with an incident bond-valence sum of 1.95 vu (valence units). The F– ion is coordinated by Li+ + Li+ + Al3+ with an incident bond-valence sum of 0.84 vu (values around F– generally tend to be lower than ideal). Thus, the valence-sum rule is satisfied, both long range and short range. In the space group C2/m, there is long-range order but not short-range order. There are three different short-range arrangements, one of which has bond-valence deficiencies of 0.38 and 0.49 vu around the non-bridging O2– ion and the F– ion, destabilizing the structure relative to the more ordered arrangement of the C2 structure, which conforms more closely to the valence-sum rule. The drive to lower the symmetry in polylithionite-1M from C2/m to C2 comes from the short-range bond-valence requirements of the structure.

Diffuse X-ray scattering and reverse Monte Carlo simulation of the short-range order in ytterbium iodine phthalocyanine [YbPc2]I2

2002 ◽  
Vol 58 (4) ◽  
pp. 622-626 ◽  
Author(s):  
J. Krawczyk ◽  
A. Pietraszko ◽  
K. Łukaszewicz
Keyword(s):  
Crystal Structure ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
X Ray ◽  
X Ray Scattering ◽  
Unit Cells ◽  
Reverse Monte Carlo Simulation ◽  
Complicated Pattern ◽  
Ray Scattering

Iodine-doped ytterbium phthalocyanine, C64H32N16YbI2, [YbPc2]I2 (YPI), presents an example of a disordered modulated crystal structure of the intergrowth type. The short-range order in YPI has been studied at ambienttemperature by the diffuse X-ray scattering technique. Both Yb and I atoms are disordered. In a unit cell of the average structure, the Yb atoms occupy two positions, \textstyle {{1} \over {2}}, \textstyle {{1} \over {2}}, \textstyle {{1} \over {4}} or \textstyle {{1} \over {2}}, \textstyle {{1} \over {2}}, \textstyle {{3} \over {4}}, with occupancy 0.5. In the neighbouring unit cells in the (001) plane there is, however, a strong tendency towards an alternating distribution of ytterbium in positions shifted by Δz = \textstyle {{1} \over {2}}. The crystal structure of YPI consists of one-dimensional columnar stacks of [{\rm YbPc} _{2} ^{2/3+}] n and of linear iodine chains [{\rm I} _{3} ^{-}] n . The modulation is commensurate since the period c I of iodine chains [{\rm I} _{3} ^{-}] n in the [001] direction is equal to one-half of the period c of the [{\rm YbPc} _{2} ^{2/3+}] n stacks. In the crystal structure, each stack of [{\rm YbPc} _{2} ^{2/3+}] n may occur in two settings shifted by c/2 and each iodine chain in three settings shifted along [001] by one-third of the period c I. The short-range order of iodine chains distributed over three settings results in a complicated pattern. Iodine chains of the same setting tend to form ribbons perpendicular to 〈100〉 and running along [001].

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