scholarly journals Structural, magnetic, and magnetocaloric properties of R2NiMnO6 (R = Eu, Gd, Tb)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. P. Shinde ◽  
E. J. Lee ◽  
M. Manawan ◽  
A. Lee ◽  
S.-Y. Park ◽  
...  
Keyword(s):  
Structural Investigation ◽  
Ceramic Powder ◽  
Double Perovskite ◽  
Considerable Change ◽  
Cooling Power ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Magnetocaloric Properties ◽  
Powder Samples ◽  
Group A

AbstractThe crystal structure, cryogenic magnetic properties, and magnetocaloric performance of double perovskite Eu2NiMnO6 (ENMO), Gd2NiMnO6 (GNMO), and Tb2NiMnO6 (TNMO) ceramic powder samples synthesized by solid-state method have been investigated. X-ray diffraction structural investigation reveal that all compounds crystallize in the monoclinic structure with a P21/n space group. A ferromagnetic to paramagnetic (FM-PM) second-order phase transition occurred in ENMO, GNMO, and TNMO at 143, 130, and 112 K, respectively. Maximum magnetic entropy changes and relative cooling power with a 5 T applied magnetic field are determined to be 3.2, 3.8, 3.5 J/kgK and 150, 182, 176 J/kg for the investigated samples, respectively. The change in structural, magnetic, and magnetocaloric effect attributed to the superexchange mechanism of Ni2+–O–Mn3+ and Ni2+–O–Mn4+. The various atomic sizes of Eu, Gd, and Tb affect the ratio of Mn4+/Mn3+, which is responsible for the considerable change in properties of double perovskite.

scholarly journals Structural, Magnetic, and Magnetocaloric Properties of R2NiMnO6 (R = Eu, Gd, Tb)

2021 ◽  
Author(s):  
K.P. Shinde ◽  
E.J. Lee ◽  
Maykel Manawan ◽  
A. Lee ◽  
S.Y. Park ◽  
...  
Keyword(s):  
Magnetic Entropy Change ◽  
Ceramic Powder ◽  
Double Perovskite ◽  
Entropy Change ◽  
Cooling Power ◽  
X Ray Diffraction ◽  
Atomic Size ◽  
X Ray ◽  
Magnetocaloric Properties ◽  
Group A

Abstract Double perovskite Eu2NiMnO6 (ENMO) Gd2NiMnO6 (GNMO) and Tb2NiMnO6 (TNMO) ceramic powder have been synthesized by solid-state reaction and their crystal structure, microstructure, cryogenic magnetic properties, and magnetocaloric performance have been investigated. Structural studies by using X-ray diffraction shows that all compounds crystallize in the monoclinic structure with a P21/n space group. A ferromagnetic to paramagnetic (FM-PM) second-order phase transition occurred in ENMO, GNMO, and TNMO around 143, 130, and 112 K, respectively. The values of maximum magnetic entropy change and relative cooling power at an applied field of 5 T are found to be 3.2, 3.8, 3.5 J/kgK and 150, 182, 176 J/kg respectively, for the studied sample. The change in structural, magnetic, and magnetocaloric effect ascribed to the superexchange mechanism of Ni2+ – O – Mn3+ and Ni2+ – O – Mn4+. Due to different atomic size of Eu, Gd, Tb changes the ratio of Mn4+/Mn3+ which is responsible for the variation of properties significantly in double perovskite.

Tailoring the Magnetic Properties and Magnetocaloric Effect in Double Perovskites Sr2FeMo1–xNbxO6

2020 ◽  
Vol 12 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Imad Hussain ◽  
S. N. Khan ◽  
Tentu Nageswara Rao ◽  
Riyaz Uddin ◽  
Jong Woo Kim ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Spontaneous Magnetization ◽  
Double Perovskite ◽  
Entropy Change ◽  
Solid State Reaction Method ◽  
Cooling Power ◽  
X Ray Diffraction ◽  
Site Disorder ◽  
Magnetocaloric Properties ◽  
Arrott Plots

The crystal structure, magnetic and magnetocaloric properties of the Sr2FeMo1–xNbxO6 (0 ≤ x ≤ 0.3) samples prepared by solid state reaction method were investigated using X-ray diffraction (XRD) and magnetic measurements. The room temperature XRD profiles obtained for all the samples revealed the formation of the double perovskite tetragonal structure with I4/mmm symmetry. Maximum values of spontaneous magnetization (17.6 emu/g at 150 K) and Curie temperature, TC (380 K) were observed in the Sr2FeMo0.9Nb0.1O6 sample indicating that low Niobium (Nb) substitution (x = 0.1) at the Mo site in the host material resulted in higher magnetization and TC. Lower values of magnetization and TC were recorded in the samples with higher Nb concentration (x = 0.2, 0.3) that was attributed to the decrease in orbital hybridization and increase in anti-site disorder resulting from heavy doping. A second order of the magnetic phase transition in each sample was confirmed by the magnetization measurements and Arrott plots. The maximum magnetic entropy change and relative cooling power (RCP) were enhanced in lowest Nb doped sample (x = 0.1) suggesting that this compound can be used in magnetic refrigeration technology.

scholarly journals Structural, magnetic and electrical properties of a new double-perovskite LaNaMnMoO 6 material

2017 ◽  
Vol 4 (11) ◽  
pp. 170920 ◽  
Author(s):  
Sameh Megdiche Borchani ◽  
Wissem Cheikh-Rouhou Koubaa ◽  
Makrem Megdiche
Keyword(s):  
Applied Field ◽  
Room Temperature ◽  
Double Perovskite ◽  
Entropy Change ◽  
Cooling Power ◽  
Room Temperature Resistivity ◽  
Ferromagnetic Transition ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Xrd Patterns

Structural, magnetic, magnetocaloric, electrical and magnetoresistance properties of an LaNaMnMoO 6 powder sample have been investigated by X-ray diffraction (XRD), magnetic and electrical measurements. Our sample has been synthesized using the ceramic method. Rietveld refinements of the XRD patterns show that our sample is single phase and it crystallizes in the orthorhombic structure with Pnma space group. Magnetization versus temperature in a magnetic applied field of 0.05 T shows that our sample exhibits a paramagnetic–ferromagnetic transition with decreasing temperature. The Curie temperature T C is found to be 320 K. Arrott plots show that all our double-perovskite oxides exhibit a second-order magnetic phase transition. From the measured magnetization data of an LaNaMnMoO 6 sample as a function of the magnetic applied field, the associated magnetic entropy change |−ΔSM| and the relative cooling power (RCP) have been determined. In the vicinity of T C , |−ΔSM| reached, in a magnetic applied field of 8 T, a maximum value of ∼4 J kg −1  K −1 . Our sample undergoes a large magnetocaloric effect at near-room temperature. Resistivity measurements reveal the presence of an insulating-metal transition at Tρ = 180 K. A magnetoresistance of 30% has been observed at room temperature for 6 T, significantly larger than that reported for the A 2 FeMoO 6 (A = Sr, Ba) double-perovskite system.

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.

Synthesis, Rietveld refinement of crystal structure, electron diffraction, and electrical transport properties of Ba2(Ca1–x–yFexNby)(Nb1–zFez)O6–δ double perovskites

2011 ◽  
Vol 89 (6) ◽  
pp. 688-696 ◽  
Author(s):  
Wang Hay Kan ◽  
Trang T. Trinh ◽  
Tobias Fürstenhaupt ◽  
Venkataraman Thangadurai
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Electrical Transport ◽  
Double Perovskite ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
Solid State Method ◽  
Boundary Conductivity ◽  
Selected Area Electron Diffraction

We report the synthesis, crystal structure, and electrochemical properties of new Fe-doped Ba2(Ca1–x–yFexNby)(Nb1–zFez)O6–δ (Fe–BCN). The Fe–BCN was synthesized by a solid-state method in air using corresponding metal oxides and salts at elevated temperature. All of the observed powder X-ray diffraction (PXRD) peaks of the investigated Fe–BCN were indexed as cubic Fm-3m (space group No. 225) double perovskite-type structure with cell constants a ∼ 8.4 Å and is consistent with selected area electron diffraction (SAED). Rietveld analysis suggested the distribution of Fe was at both 4a and 4b sites, supported the proposed chemical formula Ba2(Ca1–x–yFexNby)(Nb1–zFez)O6–δ. This was further verified by bond valence sum (BVS) analysis of the cations. The Fe–BCN showed superior chemical stability in pure CO2 and boiling H2O confirmed by PXRD and FTIR. The electrical conductivity was determined by AC impedance spectroscopy. Among the samples investigated, Ba2(Ca0.79Fe0.21)(Nb0.71Fe0.29)O6–δ showed the highest total (bulk + grain-boundary) conductivity of 1.1 × 10−2 S cm–1 in humidified (3%) N2 at 600 °C with activation energy of 0.43 eV in the temperature range 200–800 °C.

scholarly journals Preparation, Structural Analysis, and Tunability of Optical and Dielectric Characteristics of Mn–modified SrLaLiTeO6 Double Perovskite

2021 ◽  
Author(s):  
MUHAMMAD ZHARFAN MOHD HALIZAN ◽  
ZAKIAH MOHAMED ◽  
AHMAD KAMAL HAYATI YAHYA
Keyword(s):  
Dopant Concentration ◽  
Electrochemical Impedance ◽  
Double Perovskite ◽  
Optoelectronic Device ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Dielectric Characteristics ◽  
Increasing Trend ◽  
Absorption Frequencies ◽  
Optoelectronic Device Application

Abstract SrLaLiTe 1- x Mn x O 6 ( x = 0.02, 0.04, 0.06, 0.08, 0.10) double perovskites have been prepared using solid state method. Studies on structural by applying X–ray diffraction (XRD) characterization found that all compounds formed in monoclinic, P2 1 /n symmetry with reduction of lattice parameters and unit cell volume as dopant concentration increased. The formation of Te 6+ /Mn 6+ –O–Li + octahedral structure can be confirmed with the presence of peaks at certain wavenumbers indicating vibrations of Te – O or Mn – O bonds. As dopant concentration increased, field emission scanning electron microscope (FESEM) characterization found that the increasing trend of formation in grains sizes from x = 0.02 to x = 0.08, and its effects towards dielectric properties which were conducted by electrochemical impedance spectroscopy (EIS) studies were discussed in this paper. Other discussions included were regarding the significant effect of dopant towards optical band gap, E opt and absorption frequencies of prepared compounds compared to pristine compound indicating its promising potential for optoelectronic device application.

Magnetocaloric Properties of Perovskite-Type Manganite La0.65Sr0.2Na0.15MnO3

2016 ◽  
Vol 697 ◽  
pp. 93-96 ◽  
Author(s):  
Qing Ling Ji ◽  
Zheng Guang Zou ◽  
Fei Long ◽  
Yi Wu
Keyword(s):  
Curie Temperature ◽  
Magnetic Entropy Change ◽  
Sol Gel ◽  
Entropy Change ◽  
Cooling Power ◽  
Diffraction Measurement ◽  
Field Variation ◽  
X Ray Diffraction ◽  
Magnetocaloric Properties ◽  
Perovskite Type

Polycrystalline perovskite-type manganite La0.65Sr0.2Na0.15MnO3 was prepared by sol-gel method. An X-ray diffraction measurement showed that the sample was a single phase. The Curie temperature of the sample was determined to be 350K. The maximum magnetic entropy change |ΔSM| corresponding to a 1T magnetic field variation was found to be 1.08 J/kg K and about 40.6 J/kg of relative cooling power was obtained near the Curie temperature. The first-order or the second-order on the phase transition of the manganite was distinguished by Banerjee criteria.

scholarly journals Magnetocaloric effect in Sr2FeMoO6/Ag composites

2015 ◽  
Vol 9 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Mahmoud Hamad
Keyword(s):  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Double Perovskite ◽  
Entropy Change ◽  
Heat Capacity Change ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Low Field ◽  
Capacity Change ◽  
Magnetocaloric Properties

The enhanced low-field magnetocaloric effect was investigated for double perovskite Sr2FeMoO6 - silver (SFMO/Ag) composites with 0, 5 and 10 wt.% of Ag. A phenomenological model was used to predict magnetocaloric properties of SFMO/Ag composites, such as magnetic entropy change, heat capacity change and relative cooling power. It was shown that magnetic entropy change (?S M) peaks of SFMO/Ag span over a wide temperature region, which can significantly improve the global efficiency of the magnetic refrigeration. Furthermore, the ?S M distribution of the SFMO/Ag composites is much more uniform than that of gadolinium. Through these results, SFMO/Ag composite has some potential application for magnetic refrigerants in an extended high-temperature range.

scholarly journals Structural and magnetic investigation of Ca2MnReO6 doped with Ce

Cerâmica ◽  
2013 ◽  
Vol 59 (350) ◽  
pp. 262-268 ◽  
Author(s):  
J. B. Depianti ◽  
M. T. D. Orlando ◽  
A. S. Cavichini ◽  
H. P. S. Corrêa ◽  
V. A. Rodrigues ◽  
...  
Keyword(s):  
Mixed Valence ◽  
Applied Pressure ◽  
Double Perovskite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Geometric Frustration ◽  
Magnetic Investigation ◽  
Group A ◽  
Monoclinic Cell ◽  
Octahedral Distortion

We have studied the properties of Ce doping in Ca-site of Ca2MnReO6 double perovskite up to 10%. These compounds have presented a monoclinic cell with P2(1)/n space group. A small increase of lattice parameters in doped sample were observed through Rietveld refinement of X-ray diffraction pattern. The spectra at the Mn K-edge and Re L3-edge showed a mixed valence for Mn and Re in both samples. We do not observed any variation on Mn K-edge valence in XANES measurements under pressure. However a change was observed for Re L3-edge as a function of applied pressure. The Ce-doped sample showed a magnetic geometric frustration and a small decrease of the temperature frustration as compared with Ca2MnReO6 sample. The decrease of temperature frustration can be related to the MnO6 and ReO6 octahedral distortion.

Structural, magnetic, and magnetocaloric properties of multiferroic host double perovskite Pr2FeCrO6 compound

2021 ◽  
Author(s):  
Dipak Mazumdar ◽  
Indranil Das
Keyword(s):  
Crystal Structure ◽  
Magnetocaloric Effect ◽  
Ground State ◽  
Double Perovskite ◽  
X Ray Diffraction ◽  
Magnetic Ground State ◽  
X Ray ◽  
Magnetocaloric Properties

We have investigated the crystal structure and nature of the magnetic ground state of polycrystalline Pr2FeCrO6 (PFCO) compound through x-ray diffraction (XRD), magnetization, and magnetocaloric effect studies. Analysis of the...

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