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 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 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 Influence of Sr Doping on Magnetic and Magnetocaloric Properties of Nd0.6Sr0.4MnO3

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Thi Anh Ho ◽  
Huyen Ngoc Nguyen ◽  
Thang Duc Pham
Keyword(s):  
Magnetic Field ◽  
Magnetic Entropy Change ◽  
Magnetic Order ◽  
Entropy Change ◽  
Solid State Reaction Method ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Magnetocaloric Properties ◽  
Reduced Temperature ◽  
Curie Temperature Tc

Nd0.6Sr0.4MnO3 sample is fabricated by a solid-state reaction method and its magnetic, magnetocaloric properties are investigated. The Curie temperature, TC, at which a ferromagnetic-paramagnetic transition occurs is about 270 K. Based on an analysis using the Banejee’s criterion for the experiment results of magnetic-field dependences of magnetization and the universal curves of the normalized entropy change versus reduced temperature, we assess magnetic order existing in this sample. Furthermore, the maximum magnetic entropy change, which occurs near TC, measured at a magnetic field span of 50 kOe is about 6.0 J/kg.K corresponds to relative cooling power of 250 J/kg. These values are comparable to those of other manganites.

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.

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.

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.

Field Dependence of the Refrigerant Capacity for La0.6Ca0.4MnO3 Manganite

2009 ◽  
Vol 154 ◽  
pp. 163-168 ◽  
Author(s):  
R.A. Szymczak ◽  
Aleksandra Kolano-Burian ◽  
Roman Kolano ◽  
R. Puzniak ◽  
V.P. Dyakonov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Statistical Model ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Relative Cooling Power ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Refrigerant Capacity ◽  
Jahn Teller

The magnetocaloric effect in La0.6Ca0.4MnO3 manganite has been investigated. The isothermal magnetization versus applied magnetic field at various temperatures in the vicinity of Curie temperature was measured, and the temperature dependence of magnetic entropy change was determined using Maxwell’s relation. This value is comparable to that in Gd. Nevertheless, the relative cooling power of La0.6Ca0.4MnO3 was shown to be considerably lower than that of Gd. The experimental results have been analyzed in frames of a phenomenological statistical model. This model considers explicitly Jahn-Teller interactions and allows prediction of the field dependences of the magnetic entropy change and the relative cooling power.

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.

Magnetic and magnetocaloric properties of crystalline DyFe1−xMnxO3

2019 ◽  
Vol 33 (28) ◽  
pp. 1950335
Author(s):  
Fengze Cao ◽  
Hongwei Chen ◽  
Yi Lu ◽  
Jianjun Zhao ◽  
Taichao Su ◽  
...  
Keyword(s):  
Single Phase ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Cooling Capacity ◽  
X Ray Diffraction ◽  
Doping Amount ◽  
Magnetocaloric Properties ◽  
Diffraction Patterns ◽  
Average Size ◽  
Order Magnetic Phase Transition

DyFe[Formula: see text]Mn[Formula: see text]O3 (x[Formula: see text]=[Formula: see text]0, 0.025, 0.075, 0.15) polycrystalline samples were prepared using a traditional solid-state reaction route. The structural, magnetic and magnetocaloric properties of these samples were investigated. X-ray diffraction patterns showed that the samples exist as single-phase crystallines without peaks. The results of the Scanning Electron Microscopy (SEM) revealed that the average size of the polycrystalline particles decreased from 4.34 to 3.00 [Formula: see text]m as the Mn doping amount increased from 0.00 to 0.15. The magnetization versus temperature (M[Formula: see text]−[Formula: see text]T[Formula: see text]) plots showed that the order temperature of dysprosium (Dy) ions gradually decreased and the Morin-like transition temperature moved to the high-temperature region as x increased. The T[Formula: see text] gradually decreased from 13 to 10 K and the isotropic interaction of Fe[Formula: see text]-Fe[Formula: see text] was weakened as x increased from 0.00 to 0.15. The polycrystalline samples appeared as pre-formed clusters. The magnetization (M[Formula: see text]−[Formula: see text]H[Formula: see text]) plots revealed that all the samples underwent a first-order magnetic phase transition. The maximum magnetic entropy change, occurring near the Curie temperature, obtained at a magnetic-field span of 7 T, was 18.2 J/kg K. The maximum cooling capacity of the polycrystalline DyFe[Formula: see text]Mn[Formula: see text]O3 (x[Formula: see text]=[Formula: see text]0, 0.025, 0.075, 0.15) samples was 441 J/kg.

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