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.

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.

The Magnetocaloric Properties of Gd5Si4 Alloy Prepared by the New Method

2014 ◽  
Vol 4 (3) ◽  
pp. 595-600 ◽  
Author(s):  
Z. Momeni Larimi
Keyword(s):  
Magnetic Entropy Change ◽  
Entropy Change ◽  
New Method ◽  
Second Phase ◽  
Arc Furnace ◽  
Magnetic Entropy ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetocaloric Properties

We report on a new method for preparation the magnetocaloric alloy Gd5Si4. By mechanical alloying under argonatmosphere and then melting sample by arc furnace, we produced the Gd5Si4 alloy. The structure and magnetothermalproperties of the alloy have been investigated with the help of powder X-ray diffraction and magnetization measurements.This compound crystallized in the orthorhombic structure with space group pnma. In X-ray powder diffraction pattern, aminor orthorhombic GdSi2 phase was observed as a second phase. For this compound, the second order phase transitionwas observed. The maximum isothermal magnetic entropy change of the Gd5Si4 compound at 348K was found to be -10J/(kg K) in an applied field of 0.5T.

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.

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 Magnetocaloric properties of Gd(Co1-xFex)2 compounds, with x ≤ 0.60

2018 ◽  
Vol 185 ◽  
pp. 05009
Author(s):  
Maksim Anikin ◽  
Evgeniy Tarasov ◽  
Nikolay Kudrevatykh ◽  
Aleksander Zinin
Keyword(s):  
Phase Composition ◽  
Diffraction Analysis ◽  
Temperature Dependence ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Specific Magnetization ◽  
Magnetic Entropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetocaloric Properties

In this paper the results of specific magnetization and magnetocaloric effect (MCE) measurements for Gd(Co1-xFex)2 system upon the Co substitution by Fe for the x = 0 ÷ 0.60 range are presented. Phase composition was controlled by X-ray diffraction analysis. MCE has been studied within the temperature range of 300-850 K in magnetic fields up to 17 kOe by the magnetic entropy change calculation (ΔSm). It was found that in contrast to the previously studied R(Co-Fe)2 compounds where R = Dy, Ho, Er, an ordinary symmetrical peak of ΔSm(T) in the vicinity of TC is observed for presented samples. Additionally, the MCE comparison of Gd(Co0.88Fe0.12)2 with that for the isostructural Gd(Ni0.88Fe0.12)2 compound having a plateau-like ΔSm temperature dependence is given. The obtained results are discussed.

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.

The Magentocaloric Effect of Gd5Si2Ge2-XZnX Alloy

2011 ◽  
Vol 299-300 ◽  
pp. 525-529
Author(s):  
Xue Ling Hou ◽  
Jie Xiang ◽  
Zhi Zeng ◽  
Jian Huang ◽  
Xue Zhen Wang ◽  
...  
Keyword(s):  
Phase Structure ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Vibrating Sample Magnetometer ◽  
Magnetic Entropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Type Phase ◽  
Structural And Magnetic Properties ◽  
Addition Amount

The structural and magnetic properties of arc-melted alloys of Gd5Si2Ge2-xZnxin vacuum were investigated by powder x-ray diffraction and Vibrating Sample Magnetometer. When the addition amount of Zn substituted for Ge is less than or equal to 0.05, the alloys have monoclinic Gd5Si2Ge2-type phase structure, the magnetic entropy change of Gd5Si2Ge2-xZnx alloys rapidly increase, When x=0.05, the alloy has the excellent magnetic entropy change (|SM|). When the addition amount of Zn substituted for Ge is more than 0.05, the alloys have the orthorhombic Gd5Si4-type phase structure, the magnetic entropy change of Gd5Si2-xGe2-xZnxalloys rapidly decreases. The Curie temperature (Tc) of Gd5Si2Ge2-xZnx alloys linearly increases and the peak of |SM| is broader with the Zn amount substituted for Ge in Gd5Si2Ge2-xZnxalloys in x range from 0-0.15.

Magnetic, Magnetocaloric and Magnetoresonance Properties of (1-x)La0.7Sr0.3MnO3/xGeO2 (x=0, 0.15)

2019 ◽  
Vol 289 ◽  
pp. 170-176
Author(s):  
Tatiana Gavrilova ◽  
Ildar Gilmutdinov ◽  
Ivan Yatsyk ◽  
Tatiana Chupakhina ◽  
Julia Deeva ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Entropy Change ◽  
Magnetic Ordering ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Anisotropic Particles ◽  
X Ray Diffraction ◽  
Absolute Value ◽  
X Ray ◽  
Magnetic Resonance Spectra

0.85La0.7Sr0.3MnO3/0.15GeO2composite material and pure La0.7Sr0.3MnO3were investigated by X-ray diffraction, scanning electron microscopy, magnetometry and magnetic resonance methods. It was observed that both samples demonstrate the ferromagnetic properties, while the absolute value of the magnetization, the magnetic entropy change and the magnetic ordering temperature decrease in composite in comparison with pure La0.7Sr0.3MnO3. The magnetic resonance spectra of investigated (1-x)La0.7Sr0.3MnO3/xGeO2(x=0, 0.15) can be attributed to the superposition of magnetic resonance spectra from magnetically anisotropic particles with different orientations.

scholarly journals Magnetic Properties and Magnetocaloric Effect in Gd100-xCox Thin Films

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 278 ◽  
Author(s):  
Mohamed Tadout ◽  
Charles-Henri Lambert ◽  
Mohammed El Hadri ◽  
Abdelilah Benyoussef ◽  
Mohammed Hamedoun ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Thin Films ◽  
Critical Parameters ◽  
Cooling Power ◽  
Magnetocaloric Properties ◽  
Co Concentration ◽  
Key Parameter

We investigated the magnetic and magnetocaloric properties of Gd100-xCox ( x = 40 to 56) thin films fabricated by the sputtering technique. Under an applied field change Δ H = 20 kOe , the magnetic entropy change ( Δ S m ) decreases from 2.64 Jkg−1K−1 for x = 44 to about 1.27 Jkg−1K−1 for x = 56. Increasing the Co concentration from x = 40 to 56 shifts the Curie temperature of Gd100-xCox ( x = 40 to 56) thin films from 180 K toward 337 K. Moreover, we extracted the values of critical parameters Tc, β, γ, and δ by using the modified Arrott plot methods. The results indicate the presence of a long-range ferromagnetic order. More importantly, we showed that the relative cooling power (RCP), which is a key parameter in magnetic refrigeration applications, is strongly enhanced by changing the Co concentration in the Gd100-xCox thin films. Our findings help pave the way toward the enhancement of the magnetocaloric effect in magnetic thin films.

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