scholarly journals Tuning of the Structure and Magnetocaloric Effect of Mn1−xZrxCoGe Alloys (Where x = 0.03, 0.05, 0.07, and 0.1)

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3129
Author(s):  
Karolina Kutynia ◽  
Piotr Gębara
Keyword(s):  
Structural Transformation ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Rietveld Analysis ◽  
Significant Rise ◽  
Partial Substitution ◽  
Magnetic Entropy ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Zr Addition

The aim of the present work is to study the influence of a partial substitution of Mn by Zr in MnCoGe alloys. The X-ray diffraction (XRD) studies revealed a coexistence of the orthorhombic TiNiSi-type and hexagonal Ni2In- type phases. The Rietveld analysis showed that the changes in lattice constants and content of recognized phases depended on the Zr addition. The occurrence of structural transformation was detected. This transformation was confirmed by analysis of the temperature dependence of exponent n given in the relation ΔSM = C·(BMAX)n. A decrease of the Curie temperature with an increase of the Zr content in the alloy composition was detected. The magnetic entropy changes were 6.93, 13.42, 3.96, and 2.94 J/(kg K) for Mn0.97Zr0.03CoGe, Mn0.95Zr0.05CoGe, Mn0.93Zr0.07CoGe, and Mn0.9Zr0.1CoGe, respectively. A significant rise in the magnetic entropy change for samples doped by Zr (x = 0.05) was caused by structural transformation.

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.

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.

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.

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.

Large Isothermal Magnetic Entropy Change after Hydrogen Absorption into La0.5Pr0.5(Fe0.88Si0.12)13

2007 ◽  
Vol 26-28 ◽  
pp. 577-580
Author(s):  
S. Fujieda ◽  
A. Fujita ◽  
Kazuaki Fukamichi
Keyword(s):  
Hydrogen Absorption ◽  
Room Temperature ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Partial Substitution ◽  
Magnetic Entropy ◽  
Field Change ◽  
Maximum Value ◽  
Magnetic Field Change ◽  
Curie Temperature Tc

The influences of hydrogen absorption on the Curie temperature TC and the isothermal magnetic entropy change for La0.5Pr0.5(Fe0.88Si0.12)13 have been investigated, because the magnetocaloric effects have been confirmed to be enhanced after a partial substitution of Pr for La in La(Fe0.88Si0.12)13. The value of TC for La0.5Pr0.5(Fe0.88Si0.12)13Hy increases from 185 to 324 K with increasing y from 0 to 1.6. The maximum value of the isothermal magnetic entropy change ,Sm MAX is slightly decreased by hydrogen absorption. However, ,Sm MAX = -26 J/kg K in a magnetic field change of 5 T for La0.5Pr0.5(Fe0.88Si0.12)13H1.6 is still larger than the value of -23 J / kg K for La(Fe0.88Si0.12)13H1.5 having almost the same value of TC. Consequently, ,Sm MAX of the La0.5Pr0.5(Fe0.88Si0.12)13Hy is larger than that of La(Fe0.88Si0.12)13Hy in a wide temperature range covering room temperature.

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.

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