scholarly journals Zn and P Alloying Effect in Sub-Rapidly Solidified LaFe11.6Si1.4 Magnetocaloric Plates

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 432 ◽  
Author(s):  
Pingxia Jin ◽  
Yuqiang Li ◽  
Yuting Dai ◽  
Zhishuai Xu ◽  
Changjiang Song ◽  
...  
Keyword(s):  
Density Functional ◽  
Magnetic Transition ◽  
Centrifugal Casting ◽  
Entropy Change ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
P Elements ◽  
Zn Addition ◽  
Magnetic Field Change ◽  
Rapidly Solidified

The occupation mechanism and magnetic transition behavior of trace Zn and P alloying in the sub-rapidly solidified LaFe11.6Si1.4 magnetocaloric plates were investigated. The LaFe11.6Si1.4, LaFe11.6Si1.4Zn0.03, and LaFe11.6Si1.4P0.03 plates were fabricated using the centrifugal casting method in the present work. Experimental results showed that both Zn and P elements were distributed in the La5Si3 and LaFeSi phases during sub-rapid solidification. After annealed at 1373 K for 72 h, the LaFe11.6Si1.4 plate underwent a second-order magnetic transition, while both the LaFe11.6Si1.4Zn0.03 and LaFe11.6Si1.4P0.03 plates underwent a first-order transition. In combination with X-ray diffraction results, it was proposed that both Zn and P atoms prefer to enter the 96i site substituting for FeII/Si atoms according to the density-functional reconstruction of crystallographic structure. The Zn addition led to a slight decrease in magnetic entropy change from 7.0 to 5.9 J/(kg⋅K), while the P addition strikingly enhanced this property to 31.4 J/(kg⋅K) under a magnetic field change of 3 T. The effective refrigeration capacity of the annealed LaFe11.6Si1.4P0.03 plate reached 189.9 J/kg.

Magnetocaloric Properties of Rapidly Solidified Ni51.1Mn31.2In17.7 Heusler Alloy Ribbons

2009 ◽  
Vol 1200 ◽  
Author(s):  
Jose Sánchez Llamazares ◽  
Blanca Hernando ◽  
Víctor Prida ◽  
Carlos García ◽  
Caroline Ross
Keyword(s):  
Melt Spinning ◽  
Magnetic Entropy Change ◽  
Magnetic Transition ◽  
Entropy Change ◽  
Single Step ◽  
Magnetic Entropy ◽  
Refrigerant Capacity ◽  
Magnetocaloric Properties ◽  
Room Temperature Magnetic Refrigeration ◽  
Rapidly Solidified

AbstractMagnetic entropy change and refrigerant capacity have been determined for a field change of 20 kOe around the second-order magnetic transition of austenite in as-quenched Ni51.1Mn31.2In17.7 alloy ribbons produced by melt spinning technique. Samples crystallize in a single-phase austenite with the highly ordered L21-type crystal structure and a Curie temperature of 275 K. The material shows a maximum magnetic entropy change of ΔSMmax= - 1.7 Jkg-1K-1, an useful working temperature range of 78 K (δTFWHM) and a refrigerant capacity of RC=132 Jkg-1 (RC= │ΔSMmax│ x δTFWHM). The considerable RC value obtained together with the fabrication via a single-step process make austenitic Ni-Mn-In ribbons of potential interest as magnetic refrigerants for room temperature magnetic refrigeration.

Untypical Temperature Dependence of the Magnetocaloric Effect in the Dy(Co1-xFex)2 (x = 0.10; 0.15) Compounds

2015 ◽  
Vol 233-234 ◽  
pp. 247-250 ◽  
Author(s):  
Maksim S. Anikin ◽  
Evgeniy N. Tarasov ◽  
Nikolay V. Kudrevatykh ◽  
Aleksander V. Zinin
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Magnetic Entropy Change ◽  
Magnetic Transition ◽  
Iron Concentration ◽  
Entropy Change ◽  
Cooling Power ◽  
X Ray Diffraction ◽  
Magnetocaloric Properties ◽  
Ordered State

A study of crystalline structure, magnetic and magnetocaloric properties of Dy(Co1-хFeх)2 (х = 0.10, 0.15) intermetallic compounds was undertaken. Phase composition was controlled by X-ray diffraction analysis. Magnetic properties were measured with a help of SQUID magnetometer in magnetic fields up to 7 Т in the temperature range from 4.2 K to 400 K. Magnetic transition temperatures from paramagnetic to magnetically ordered state were inferred as 288 K and 350 K, respectively. It is shown that at an increase of iron concentration and/or magnetic field intensity, a considerable maximum broadenings on a temperature dependence of magnetic entropy change is observed. The calculated value of the relative cooling power (RCP) of Dy(Co0.90Fe0.10)2, in a magnetic field of 1.7 T is equal to 152 J/kg that is close to that for Gd metal with RCP = 181 J/kg at μ0Н = 2 T.

scholarly journals Growth, Crystal Structure, Hirshfeld Surface Analysis, DFT Studies, Physicochemical Characterization And Cytotoxicity Assays of Novel Organic Triphosphate

2021 ◽  
Author(s):  
Yathreb Oueslati ◽  
Sevgi Kansız ◽  
Necmi Dege ◽  
Cristina de la Torre Paredes ◽  
Antoni Llopis Lorente ◽  
...  
Keyword(s):  
Density Functional ◽  
Three Dimensional ◽  
Physicochemical Characterization ◽  
Basis Set ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Hybrid Compound ◽  
X Ray ◽  
Molecular Arrangement ◽  
Chemical Procedure

Abstract A novel interesting organic-inorganic hybrid compound, named (1-phenylpiperazinium) trihydrogen triphosphate, with the formula (C10H15N2)2H3P3O10 has been obtained by low speed of evaporation at room temperature after using the ion exchange chemical procedure. To carry out a detailed crystallographic structure analysis, single-crystal X-ray diffraction has been reported. In the molecular arrangement, the different entities are held together through N-H…O, O-H…O and C-H…O hydrogen bonds, building up a three dimensional packing. Powder X-ray diffraction analysis is acquired to confirm the purity of the product. The nature and the proportion of intermolecular interactions were investigated by Hirshfeld surfaces analysis. In order to support the experimental results, a density functional theory (DFT) calculation were performed, using the Becke-3-Parameter-Lee-Yang-Parr (B3LYP) function with LANL2DZ basis set, and the data indicate the much agreement between the experimental and the theoretical results. Thus, the physicochemical properties were studied employing a variety of techniques (FT-IR, NMR, UV-Visible and photoluminescence). To get an insight of the possible employment of the present material in biology, cell viability assays were performed.

A study of eutectic indium-bismuth and indium-bismuth-tin Field’s metal rapidly solidified from melt

2015 ◽  
Vol 7 (2) ◽  
pp. 1404-1413 ◽  
Author(s):  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
RizkMostafa Shalaby ◽  
Mohammed Younus
Keyword(s):  
Specific Heat ◽  
Elastic Moduli ◽  
Magnetic Force ◽  
Thermal Effusivity ◽  
Entropy Change ◽  
Eutectic Alloys ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Rapidly Solidified

In this paper, the microstructure and thermal behavior of two rapidly solidified of eutectic Indium-Bismuth and Indium-Bismuth-Tin Field’s metal are reported. This work experimentally measures the specific heat of the eutectic alloys of the binary Indium-bismuth and indium –bismuth –tin tertiary system using a differential scanning calorimeter (DSC) technique and analyzes the results to determine the thermodynamic properties of the system have sufficient scaling for experimental modeling applications. The resultant ribbons were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) techniques, energy dispersive x-ray (EDX) technique. From the differential scanning calorimetry measurements, it is found that entropy change, enthalpy and specific heat are improved and enhanced compared with literature. The electrical resistivity was reported for temperatures between 295 and 330 K for all the melt-quenched ribbons of binary In-49Biand tertiary In-32.5 Bi -16.5 Sn (wt.%). The microhardness, elastic moduli, internal friction and both thermal diffusivity and thermal effusivity were also measured. Field’s metal is more than suitable for use in experimental settings as it is non-reactive, non-toxic, simple to manufacture, easy to use, and responds to a magnetic force.

Magnetic Properties and Structural Transitions in (MnCo)1-xGe

2009 ◽  
Vol 152-153 ◽  
pp. 489-492 ◽  
Author(s):  
P.E. Markin ◽  
N.V. Mushnikov
Keyword(s):  
Magnetic Field ◽  
Structural Transition ◽  
Magnetic Phase ◽  
Hexagonal Phase ◽  
Magnetic Transition ◽  
Entropy Change ◽  
Paramagnetic State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isothermal Regime

The magnetic and X-ray diffraction measurements of the ferromagnetic compounds (MnCo)1-xGe have been performed for the concentration range 0 ≤ x ≤ 0.05. The structural and magnetic phase diagrams have been obtained. Compositions for which the magnetic transition from ferromagnetic to paramagnetic state coincides with the structural transition from an orthorhombic to a hexagonal phase have been determined to be 0.015 ≤ x ≤ 0.025. It was found that for the compound with x = 0.015 application of 1 T magnetic field in isothermal regime in the vicinity of the Curie temperature is accompanied by the entropy change 1.3 J/(Kkg).

Effect of Small Amount of Zn Additions on the Magnetocaloric Properties of Gd5Si2Ge2 Alloy

2011 ◽  
Vol 685 ◽  
pp. 307-310
Author(s):  
Xue Zhen Wang ◽  
Jie Xiang ◽  
Zhi Zeng ◽  
Xing Hao Hu ◽  
Xue Ling Hou ◽  
...  
Keyword(s):  
Magnetocaloric Effect ◽  
Monoclinic Phase ◽  
Magnetic Entropy Change ◽  
Orthorhombic Phase ◽  
Entropy Change ◽  
Type Structure ◽  
X Ray Diffraction ◽  
Arc Melting ◽  
Magnetocaloric Properties ◽  
Magnetic Field Change

The structural and magnetic property of Gd5Si1.99Ge2Zn0.01and Gd5Si2Ge2 alloys prepared by arc-melting the starting materials with commercial available purity (99.95wt%) was investigated by x-ray diffraction and Vibrating Sample Magnetometer. The result shows that the Gd5Si1.99Ge2Zn0.01alloy has monoclinic phase with Gd5Si2Ge2-type structure. The polymorphic orthorhombic phase with Gd5Si4-type structure coexists with the monoclinic phase in Gd5Si2Ge2alloy. The addition of small Zn element in Gd5Si2Ge2alloy results in a considerable enhancement of its magnetocaloric effect. The maximum magnetic entropy change rapidly increases from 5.03J/(kg K) to 20.70J/(kg K) for a magnetic field change from 0 to 1.5T. The magnetic order temperature is 278K in Gd5Si1.99Ge2Zn0.01alloy and 278.5K in Gd5Si2Ge2 alloy respectively. The magnetocaloric effect of Gd5Si2Ge2 with the small addition of Zn is significantly improved.

scholarly journals Thermomagnetic Correlation in La0.85-xBixNa0.15MnO3 Soft Ferromagnet due to Nonmagnetic Bi3+ Substitution

2021 ◽  
Author(s):  
Lozil Denzil Mendonca ◽  
M. S. Murari ◽  
Mamatha D. Daivajna
Keyword(s):  
Magnetic Entropy Change ◽  
Magnetic Transition ◽  
Entropy Change ◽  
Rhombohedral Structure ◽  
Magnetic Entropy ◽  
Griffiths Phase ◽  
X Ray Diffraction ◽  
Magnetic Transition Temperature ◽  
Magnetocaloric Properties ◽  
Room Temperature Magnetic Refrigeration

AbstractWe report the structural, magnetic, and magnetocaloric properties of Bismuth (Bi)-substituted manganite La0.85-xBixNa0.15MnO3 (x=0, 0.1, 0.2, 0.25, and 0.3). X-ray diffraction data implicates the rhombohedral structure with $$ R\overline{3}c $$ R 3 ¯ c space group. Bi2O3 has helped in ensuring phase pure, densified compounds even at low sintering temperature and hence avoiding the evaporation of volatile sodium. The increase in grain size and decrease in magnetic transition temperature (TC) are due to the Bi chemical activity and electronic structure. The samples have shown indirect magnetic transformation from soft ferromagnet to canted ferromagnet/antiferromagnet with Bi. Griffiths phase-like behavior in the inverse magnetic susceptibility was observed for x=0.1; with further increase in Bi, the samples are found to develop the antiferromagnetic competing phase. The phenomenological model was used to model the thermomagnetic behavior of all the samples. The sample with x=0.1 shows an increase in magnetic entropy change upon Bi substitution and the maximum of magnetic entropy change is seen at 275K emphasizing its potential in room temperature magnetic refrigeration.

Devitrification products of rapidly solidified Ni-Nb amorphous alloys.

1990 ◽  
Vol 48 (4) ◽  
pp. 950-951
Author(s):  
G. A. Bertero ◽  
W.H. Hofmeister ◽  
N.D. Evans ◽  
J.E. Wittig ◽  
R.J. Bayuzick
Keyword(s):  
Electron Microscopy ◽  
Amorphous Structure ◽  
Sulphuric Acid Solution ◽  
X Ray Diffraction ◽  
High Fracture ◽  
Transmission Electron ◽  
Xrd Techniques ◽  
Rapidly Solidified ◽  
Electromagnetically Levitated

Rapid solidification of Ni-Nb alloys promotes the formation of amorphous structure. Preliminary results indicate promising elastic properties and high fracture strength for the metallic glass. Knowledge of the thermal stability of the amorphus alloy and the changes in properties with temperature is therefore of prime importance. In this work rapidly solidified Ni-Nb alloys were analyzed with transmission electron microscopy (TEM) during in-situ heating experiments and after isothermal annealing of bulk samples. Differential thermal analysis (DTA), scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were also used to characterize both the solidification and devitrification sequences.Samples of Ni-44 at.% Nb were electromagnetically levitated, melted, and rapidly solidified by splatquenching between two copper chill plates. The resulting samples were 100 to 200 μm thick discs of 2 to 3 cm diameter. TEM specimens were either ion-milled or alternatively electropolished in a methanol-10% sulphuric acid solution at 20 V and −40°C.

Design and Synthesis of Two-Dimensional Covalent Organic Frameworks with Four-Arm Cores: Prediction of Remarkable Ambipolar Charge-Transport Properties

2019 ◽  
Author(s):  
Simil Thomas ◽  
Hong Li ◽  
Raghunath R. Dasari ◽  
Austin Evans ◽  
William Dichtel ◽  
...  
Keyword(s):  
Charge Transport ◽  
Organic Semiconductors ◽  
Density Functional ◽  
Polymer Networks ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
X Ray Diffraction ◽  
Zinc Porphyrin ◽  
Design And Synthesis ◽  
Predicted Values

<p>We have considered three two-dimensional (2D) π-conjugated polymer networks (i.e., covalent organic frameworks, COFs) materials based on pyrene, porphyrin, and zinc-porphyrin cores connected <i>via</i> diacetylenic linkers. Their electronic structures, investigated at the density functional theory global-hybrid level, are indicative of valence and conduction bands that have large widths, ranging between 1 and 2 eV. Using a molecular approach to derive the electronic couplings between adjacent core units and the electron-vibration couplings, the three π-conjugated 2D COFs are predicted to have ambipolar charge-transport characteristics with electron and hole mobilities in the range of 65-95 cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup>. Such predicted values rank these 2D COFs among the highest-mobility organic semiconductors. In addition, we have synthesized the zinc-porphyrin based 2D COF and carried out structural characterization via powder X-ray diffraction and surface area analysis, which demonstrates the feasability of these electroactive networks.</p>

scholarly journals Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5970
Author(s):  
Nabil Al-Zaqri ◽  
Mohammed Suleiman ◽  
Anas Al-Ali ◽  
Khaled Alkanad ◽  
Karthik Kumara ◽  
...  
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Structural Parameters ◽  
Population Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Td Dft

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2–sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.

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