Effects of carbon doping on structure and magnetocaloric properties of Mn1.25Fe0.7P0.5Si0.5 alloys

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jimei Niu ◽  
Zhigang Zheng
Keyword(s):  
Magnetic Field ◽  
Entropy Change ◽  
Type Structure ◽  
Carbon Doping ◽  
Sintering Process ◽  
Arc Melting ◽  
Magnetocaloric Properties ◽  
C Doping ◽  
Room Temperature Magnetic Refrigeration ◽  
P Type

Abstract (Mn,Fe)2(P,Si)-basedmaterials are promisingly applied in the room-temperature magnetic refrigeration field. In this study, Mn1.25Fe0.7P0.5Si0.5Cx (x = 0, 0.01, 0.03 and 0.05) alloys were prepared by arc-melting and then a two-stage sintering process. The effects of C doping on the crystal structure and magnetocaloric behavior are discussed. Results indicate that the Fe2P-type structure (space group of P62 m) was crystallized for all samples with weakened first-order magnetic transitions (FOMT). The Curie temperature could be altered from 223.5 K to 278.5 K with the large magnetocaloric effect (MCE) remaining by C doping. In the applied magnetic field of 5 T, the peak value of magnetic entropy change (–ΔS M) increased by 7.3% to reach 25.1 J × kg–1 × K–1. The temperature-induced entropy change (ΔS DSC) derived from DSC was slightly larger than ΔS M induced by the magnetic field. The Mn1.25Fe0.7P0.5Si0.5 alloys with large MCE can be effectively tuned by C doping because C atoms prefered to share the substitute and occupy the interstitial sites in hexagonal Fe2P-type structure.

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.

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 Magnetocaloric Effect in Cu5-NIPA Molecular Magnet: A Theoretical Study

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 485 ◽  
Author(s):  
Karol Szałowski ◽  
Pamela Kowalewska
Keyword(s):  
Magnetic Field ◽  
Magnetocaloric Effect ◽  
Theoretical Study ◽  
Canonical Ensemble ◽  
Entropy Change ◽  
Molecular Magnet ◽  
Wide Range ◽  
Magnetocaloric Properties ◽  
Magnetic Specific Heat ◽  
High Degree

We calculated the magnetocaloric properties of the molecular nanomagnet Cu5-NIPA, consisting of five spins S = 1 / 2 arranged in two corner-sharing triangles (hourglass-like structure without magnetic frustration). The thermodynamics of the system in question was described using the quantum Heisenberg model solved within the field ensemble (canonical ensemble) using exact numerical diagonalization. The dependence of the magnetic entropy and magnetic specific heat on the temperature and the external magnetic field was investigated. The isothermal entropy change for a wide range of initial and final magnetic fields was discussed. Due to plateau-like behavior of the isothermal entropy change as a function of the temperature, a high degree of tunability of magnetocaloric effect with the initial and final magnetic field was demonstrated.

The Effect of Plastic Deformation on Magnetic and Magnetocaloric Properties of Gd90Ga10 Alloy

2016 ◽  
Vol 845 ◽  
pp. 56-60 ◽  
Author(s):  
Sergey Taskaev ◽  
Konstantin Skokov ◽  
Dmitriy Karpenkov ◽  
Vladimir V. Khovaylo ◽  
Maxim N. Ulyanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Magnetocaloric Effect ◽  
Entropy Change ◽  
High Temperature Heat Treatment ◽  
Magnetocaloric Properties ◽  
Temperature Heat ◽  
Cold Rolled ◽  
Temperature Heat Treatment

In this work we report the results of experimental investigation of the magnetocaloric effect in Gd90Ga10 cold rolled ribbons. A moderate entropy change ΔS = 3.5 J/(kg·K) and magnetocaloric effect ΔT = 3.4K was observed for the as-cast materials in an external magnetic field of 2T which is less by 35% in comparison with the pure gadolinium metal. It was found that a significant (up to 70%) depression of magnetization and magnetocaloric properties developed in the course of plastic deformation can be completely restored by means of a high temperature heat treatment.

scholarly journals Magnetic and Magneto-Caloric Properties of the Amorphous Fe92−xZr8Bx Ribbons

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5334
Author(s):  
Xin Wang ◽  
Qiang Wang ◽  
Ben Zhen Tang ◽  
Ding Ding ◽  
Li Cui ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
Maximum Entropy ◽  
Entropy Change ◽  
Boron Addition ◽  
Magnetocaloric Properties ◽  
Curie Temperature Tc

Magnetic and magnetocaloric properties of the amorphous Fe92−xZr8Bx ribbons were studied in this work. Fully amorphous Fe89Zr8B3, Fe88Zr8B4, and Fe87Zr8B5 ribbons were fabricated. The Curie temperature (Tc), saturation magnetization (Ms), and the maximum entropy change with the variation of a magnetic field (−ΔSmpeak) of the glassy ribbons were significantly improved by the boron addition. The mechanism for the enhanced Tc and −ΔSmpeak by boron addition was studied.

scholarly journals Tuning Magnetocaloric Properties for La-=SUB=-1-x-=/SUB=-Sr-=SUB=-x-=/SUB=-CoO-=SUB=-3-=/SUB=-

2021 ◽  
Vol 63 (10) ◽  
pp. 1551
Author(s):  
E.M. Ahmed ◽  
H.R. Alamri ◽  
S.M. Elghnam ◽  
O. Eldarawi ◽  
T.E. Tawfik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Paramagnetic State ◽  
Magnetic Entropy ◽  
Magnetocaloric Properties ◽  
Low Magnetic Field

Low magnetic field magnetocaloric (MC) properties of La1-xSrxCoO3 (x=0.3 and 0.5) near phase transition from a ferromagnetic to a paramagnetic state were investigated. It is shown that the change of Sr content allows MC effect in La1-xSrxCoO3 to be tunable, which is more practical for construction of MC refrigeration. MC properties of the x=0.5 sample are significantly greater than that of the x=0.3 one. Furthermore, the results show that MC properties of La1-xSrxCoO3 samples are significantly larger, and comparable with some MC properties of many materials like Gd1-xCaxBaCo2O5.5 and Ge0.95Mn0.05. Keywords: magnetocaloric effect, La1-xSrxCoO3, magnetic entropy change.

Magnetocaloric Effect in Ho-Er-Gd-Co Multicomponent Compounds

2012 ◽  
Vol 190 ◽  
pp. 303-306
Author(s):  
J. Ćwik ◽  
T. Palewski ◽  
K. Nenkov ◽  
J. Lyubina ◽  
Oliver Gutfleisch
Keyword(s):  
Magnetic Field ◽  
Magnetocaloric Effect ◽  
Solid Solutions ◽  
Entropy Change ◽  
Step Motor ◽  
X Ray Diffraction ◽  
Magnetocaloric Properties ◽  
Diffraction Patterns ◽  
Heat Capacity Measurements ◽  
Type Magnet

We report magnetic and magnetocaloric properties of polycrystalline series of the (Ho0.9Er0.1)1-xGdxCo2(x = 0.05, 0.1 and 0.15) solid solutions. These samples were synthesized using high purity rare earth metals and cobalt. X-ray diffraction patterns taken at room temperature reveal that all compounds have the C15 cubic Laves phase structure. Magnetization measurements were carried out using a vibration sample magnetometer with a step motor in fields up to 14 T using a Bitter-type magnet. Heat capacity measurements have been performed in the temperature range of 2-300 K without magnetic field and in a magnetic field of 1 and 2 T. The magnetocaloric effect has been estimated in terms of isothermal magnetic entropy change for all solid solutions in magnetic fields up to 3 T. The effect of increasing Gd amount in (Ho0.9Er0.1)1-xGdxCo2on the magnetic and magnetocaloric properties will be discussed.

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.

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