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Dastanpour Hosseinabadi, E., Huang, S., Ström, V., Varga, L. K., Vitos, L. & Schönecker, S. (2024). An assessment of the Al50Cr21-xMn17+xCo12 (x=0, 4, 8) high-entropy alloys for magnetocaloric refrigeration application. Journal of Alloys and Compounds, 984, 173977, Article ID 173977.
Open this publication in new window or tab >>An assessment of the Al50Cr21-xMn17+xCo12 (x=0, 4, 8) high-entropy alloys for magnetocaloric refrigeration application
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2024 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 984, p. 173977-, article id 173977Article in journal (Refereed) Published
Abstract [en]

This study investigates the magnetocaloric potential of the Al50Cr21-xMn17+xCo12 (x=0, 4, 8 at%) high-entropy alloy (HEA) series using integrated experimental and theoretical approaches. Structural analysis by X-ray diffraction and scanning electron microscopy indicate a dual phase containing B2 and body-centered cubic (BCC) structures. Magnetic characterization shows an approximately linear decrease in saturation magnetization and Curie temperature with increasing Cr content. Curie temperatures calculated by Monte Carlo simulations suggest that the measured magnetic properties originate from the B2 phase rather than the BCC phase. The enhanced magnetocaloric effect with decreasing Cr content highlights the attractiveness of HEAs in magnetocaloric applications.

Place, publisher, year, edition, pages
Elsevier Ltd, 2024
Keywords
B2 structure, High entropy alloys, Magnetic properties, Magnetocaloric effect, Monte Carlo
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-344344 (URN)10.1016/j.jallcom.2024.173977 (DOI)2-s2.0-85186459945 (Scopus ID)
Note

QC 20240314

Available from: 2024-03-13 Created: 2024-03-13 Last updated: 2024-03-14Bibliographically approved
Huang, S., Dastanpour Hosseinabadi, E., Schönecker, S., Ström, V., Chai, G., Kiss, L. F., . . . Vitos, L. (2023). Combinatorial design of partial ordered Al-Cr-Mn-Co medium-entropy alloys for room temperature magnetic refrigeration applications. Applied Physics Letters, 123(4), Article ID 044103.
Open this publication in new window or tab >>Combinatorial design of partial ordered Al-Cr-Mn-Co medium-entropy alloys for room temperature magnetic refrigeration applications
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2023 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 123, no 4, article id 044103Article in journal (Refereed) Published
Abstract [en]

Multi-component alloys have received increasing interest for functional applications in recent years. Here, we explore the magnetocaloric response for Al-Cr-Mn-Co medium-entropy alloys by integrated theoretical and experimental methods. Under the guidance of thermodynamic and ab initio calculations, a dual-phase system with large magnetic moment, i.e., Al50Cr19Mn19Co12, is synthesized, and the structural and magnetocaloric properties are confirmed via characterization. The obtained results indicate that the selected alloy exhibits a co-continuous mixture of a disordered body-centered cubic and an ordered B2 phase. The ab initio and Monte Carlo calculations indicate that the presence of the ordered B2 phase is responsible for the substantial magnetocaloric effect. The magnetization measurements demonstrated that this alloy undergoes a second-order magnetic transition with the Curie temperature of ∼300 K. The magnetocaloric properties are examined using magnetic entropy change, refrigeration capacity, and adiabatic temperature change. The property-directed strategy explored here is intended to contribute to the study of potential multi-component alloys in magnetocaloric applications.

Place, publisher, year, edition, pages
AIP Publishing, 2023
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-334743 (URN)10.1063/5.0160477 (DOI)001036269500006 ()2-s2.0-85166122676 (Scopus ID)
Note

QC 20230824

Available from: 2023-08-24 Created: 2023-08-24 Last updated: 2023-08-24Bibliographically approved
Dastanpour Hosseinabadi, E., Huang, S., Dong, Z., Schönecker, S., Ström, V., Eriksson, O., . . . Vitos, L. (2023). Investigation of the metastable spinodally decomposed magnetic CrFe-rich phase in Al doped CrFeCoNi alloy. Journal of Alloys and Compounds, 939, 168794, Article ID 168794.
Open this publication in new window or tab >>Investigation of the metastable spinodally decomposed magnetic CrFe-rich phase in Al doped CrFeCoNi alloy
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2023 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 939, p. 168794-, article id 168794Article in journal (Refereed) Published
Abstract [en]

We have conducted an in-depth study of the magnetic phase due to a spinodal decomposition of the BCC phase of a CrFe-rich composition. This magnetic phase is present after casting (arc melting) or water quenching after annealing at 1250 degrees C for 24 h but is entirely absent after annealing in the interval 900-1100 degrees C for 24 h. Its formation is favored in the temperature interval ca 450-550 degrees C and loses magnetization above 640 degrees C. This ferromagnetic-paramagnetic transition is due to a structural transformation from ferromagnetic BCC into paramagnetic sigma and FCC phases. The conclusion from measurements at different heating rates is that both the transformation leading to the increase of the magnetization due to the spinodal decomposition of the parent phase and the vanishing magnetization at 640 degrees C are diffusion controlled.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
High entropy alloy, AlCrFeCoNi, Spinodal decomposition, Structural transformation, Magnetization
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-329905 (URN)10.1016/j.jallcom.2023.168794 (DOI)000996492500001 ()2-s2.0-85146081676 (Scopus ID)
Note

QC 20230626

Available from: 2023-06-26 Created: 2023-06-26 Last updated: 2023-06-26Bibliographically approved
Masood, A., Belova, L. & Ström, V. (2023). Magnetization dynamics and spin-glass-like origins of exchange-bias in Fe-B-Nb thin films. Journal of Applied Physics, 134(24), Article ID 243903.
Open this publication in new window or tab >>Magnetization dynamics and spin-glass-like origins of exchange-bias in Fe-B-Nb thin films
2023 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 134, no 24, article id 243903Article in journal (Refereed) Published
Abstract [en]

The phenomenon of exchange bias has been extensively studied within crystalline materials, encompassing a broad spectrum from nanoparticles to thin-film systems. Nonetheless, exchange bias in amorphous alloys has remained a relatively unexplored domain, primarily owing to their inherently uniform disordered atomic structure and lacking grain boundaries. In this study, we present a unique instance of exchange bias observed in Fe-B-Nb amorphous thin films, offering insights into its origins intertwined with the system's spin-glass-like behavior at lower temperatures. The quantification of exchange bias was accomplished through a meticulous analysis of magnetic reversal behaviors in the liquid-helium temperature range, employing a zero-field cooling approach from various initial remanent magnetization states (±MR). At reduced temperatures, the appearance of asymmetric hysteresis, a hallmark of negative exchange bias, undergoes a transformation into symmetric hysteresis loops at elevated temperatures, underscoring the intimate connection between exchange-bias and dynamic magnetic states. Further investigations into the magnetic thermal evolution under varying probe fields reveal the system's transition into a spin-glass-like state at low temperatures. We attribute the origin of this unconventional exchange bias to the intricate exchange interactions within the spin-glass-like regions that manifest at the interfaces among highly disordered Fe-nuclei. The formation of Fe-nuclei agglomerates at the sub-nanometer scale is attributed to the alloy's limited glass-forming ability and the nature of the thin-film fabrication process. We propose that this distinctive form of exchange bias represents a novel characteristic of amorphous thin films.

Place, publisher, year, edition, pages
AIP Publishing, 2023
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-342184 (URN)10.1063/5.0179602 (DOI)2-s2.0-85181102095 (Scopus ID)
Note

QC 20240115

Available from: 2024-01-15 Created: 2024-01-15 Last updated: 2024-02-06Bibliographically approved
Dastanpour Hosseinabadi, E., Huang, S., Schönecker, S., Mao, H., Ström, V., Eriksson, O., . . . Vitos, L. (2023). On the structural and magnetic properties of Al-rich high entropy alloys: a joint experimental-theoretical study. Journal of Physics D: Applied Physics, 56(1), Article ID 015003.
Open this publication in new window or tab >>On the structural and magnetic properties of Al-rich high entropy alloys: a joint experimental-theoretical study
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2023 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 56, no 1, article id 015003Article in journal (Refereed) Published
Abstract [en]

The present work investigates how the vanadium (V) content in a series of Al50V (x) (Cr0.33Mn0.33Co0.33)((50-x)) (x = 12.5, 6.5, 3.5, and 0.5 at.%) high-entropy alloys affects the local magnetic moment and magnetic transition temperature as a step towards developing high-entropy functional materials for magnetic refrigeration. This has been achieved by carrying out experimental investigations on induction melted alloys and comparison to ab initio and thermodynamic calculations. Structural characterization by x-ray diffraction and scanning electron microscopy indicates a dual-phase microstructure containing a disordered body-centered cubic (BCC) phase and a B2 phase with long-range order, which significantly differ in the Co and V contents. Ab initio calculations demonstrate a weaker magnetization and lower magnetic transition temperature (T

Place, publisher, year, edition, pages
IOP Publishing, 2023
Keywords
magnetic materials, high entropy alloys, ab initio, B2 structure, magnetic transition temperature, V content
National Category
Condensed Matter Physics Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-323091 (URN)10.1088/1361-6463/aca1ce (DOI)000897771000001 ()2-s2.0-85144560264 (Scopus ID)
Note

QC 20230118

Available from: 2023-01-18 Created: 2023-01-18 Last updated: 2023-01-18Bibliographically approved
Hoogendoorn, B. W., Birdsong, B. K., Capezza, A. J., Ström, V., Li, Y., Xiao, X. & Olsson, R. (2022). Ultra-low Concentration of Cellulose Nanofibers (CNFs) for Enhanced Nucleation and Yield of ZnO Nanoparticles. Langmuir, 38(41), 12480-12490
Open this publication in new window or tab >>Ultra-low Concentration of Cellulose Nanofibers (CNFs) for Enhanced Nucleation and Yield of ZnO Nanoparticles
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2022 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 38, no 41, p. 12480-12490Article in journal (Refereed) Published
Abstract [en]

Cellulose nanofibers (CNFs) were used in aqueous synthesis protocols for zinc oxide (ZnO) to affect the formation of the ZnO particles. Different concentrations of CNFs were evaluated in two different synthesis protocols producing distinctly different ZnO morphologies (flowers and sea urchins) as either dominantly oxygen-or zinc-terminated particles. The CNF effects on the ZnO formation were investigated by implementing a heat-treatment method at 400 degrees C that fully removed the cellulose material without affecting the ZnO particles made in the presence of CNFs. The inorganic phase formations were monitored by extracting samples during the enforced precipitations to observe changes in the ZnO morphologies. A decrease in the size of the ZnO particles could be observed for all synthesis protocols, already occurring at small additions of CNFs. At as low as 0.1 g/L CNFs, the particle size decreased by 50% for the flower-shaped particles and 45% for the sea-urchin-shaped particles. The formation of smaller particles was accompanied by increased yield by 13 and 15% due to the CNFs' ability to enhance the nucleation, resulting in greater mass of ZnO divided among a larger number of particles. The enhanced nucleation could also be verified as useful for preventing secondary morphologies from forming, which grew on the firstly precipitated particles. The suppression of secondary growths' was due to the more rapid inorganic phase formation during the early phases of the reactions and the faster consumption of dissolved salts, leaving smaller amounts of metal salts present at later stages of the reactions. The findings show that using cellulose to guide inorganic nanoparticle growth can be predicted as an emerging field in the preparation of functional inorganic micro/nanoparticles. The observations are highly relevant in any industrial setting for the large-scale and resource-efficient production of ZnO.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:kth:diva-321261 (URN)10.1021/acs.langmuir.2c01713 (DOI)000874223000001 ()36200128 (PubMedID)2-s2.0-85139961062 (Scopus ID)
Note

QC 20221111

Available from: 2022-11-11 Created: 2022-11-11 Last updated: 2023-05-17Bibliographically approved
Dastanpour, E., Enayati, M. H., Masood, A. & Ström, V. (2021). Crystallization behavior, soft magnetism and nanoindentation of Fe–Si–B–P–Cu alloy on Ni substitution. Journal of Alloys and Compounds, 851, Article ID 156727.
Open this publication in new window or tab >>Crystallization behavior, soft magnetism and nanoindentation of Fe–Si–B–P–Cu alloy on Ni substitution
2021 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 851, article id 156727Article in journal (Refereed) Published
Abstract [en]

The present work investigates how the substitution of Ni for Fe in the amorphous precursor of the high flux density Fe–Si–B–P–Cu (Nanomet®) alloy avoids the creation of detrimental pre-existing nuclei in the amorphous precursor as a step forward for improved amorphization capability, retains homogenous nanocrystalline structure with excellent soft magnetic properties, and affects the mechanical properties in terms of reduced hardness and Young's modulus. This has been achieved by adding Ni of various concentrations (0–8 atomic %). The investigation includes structural characterization, calorimetry, optimization of annealing temperature, extensive magnetic characterization and nanoindentation to assess the mechanical properties. The excellent soft magnetic properties demonstrate a strategy to deploy the nanocrystalline ribbons where freedom of device design is a limiting factor for electrodynamic energy conversion applications.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
Nanocrystalline, Nanoindentation, Nanomet, Ni-substitution, Soft magnetic properties, Amorphous silicon, Copper alloys, Crystallization, Density (specific gravity), Elastic moduli, Energy conversion, Magnetic properties, Magnetism, Nanocrystals, Amorphous precursors, Annealing temperatures, Crystallization behavior, Magnetic characterization, Nano-crystalline structures, Nanocrystalline ribbon, Structural characterization, Nanocrystalline alloys
National Category
Metallurgy and Metallic Materials Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-285275 (URN)10.1016/j.jallcom.2020.156727 (DOI)000579868900025 ()2-s2.0-85089884729 (Scopus ID)
Note

Correction in:Journal Of Alloys And Compounds

Volume:878; Article Number 160527; DOI10.1016/j.jallcom.2021.160527;

Accession Number WOS:000660479000005

Available from: 2020-12-03 Created: 2020-12-03 Last updated: 2022-09-26Bibliographically approved
Masood, A., Baghbaderani, H. A., Alvarez, K. L., Blanco, J. M., Pavlovic, Z., Ström, V., . . . McCloskey, P. (2021). High-frequency power loss mechanisms in ultra-thin amorphous ribbons. Journal of Magnetism and Magnetic Materials, 519, Article ID 167469.
Open this publication in new window or tab >>High-frequency power loss mechanisms in ultra-thin amorphous ribbons
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2021 (English)In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 519, article id 167469Article in journal (Refereed) Published
Abstract [en]

Soft magnetic amorphous materials with ultra-low power loss are highly desirable for high-frequency drive applications. The present work demonstrates the high-frequency power loss performance and underlying loss mechanisms in ultra-thin amorphous alloys. This is achieved by rapid-quenching amorphous alloys of Co-, CoFe- and Fe-rich systems, investigating their amorphous atomic structure, quantifying the saturation magnetostriction constants (λs), imaging magnetic domains at remanent magnetization, analyzing magnetization reversal from various magnetization levels, and finally, investigating the material loss performance over a broad frequency range (f = 50 kHz–2 MHz) at various excitation levels (Bm = 25–100 mT). The ultra-high performance of ultra-thin Co-rich amorphous ribbons, as compared to CoFe- and Fe-rich alloys, was attributed to the significantly low eddy current loss, due to the reduced thickness, and a minimal amount of excess loss, owning to minimal magnetoelastic contributions and magnetization reversal by rotation. The underlying loss mechanisms were analyzed by decomposing material loss into primary components and identifying the magnetization reversal mechanisms using minor hysteresis loops. In the Co-rich amorphous alloys, we suggest that magnetization reversal by rotation dominates, at least at low excitations, while in CoFe- and Fe-rich alloys domain wall displacement prevails and contributes significantly to the excess loss up to the MHz frequency range. Magnetization reversal by rotation in Co-rich alloys could be attributed to the zero/near-zero λs, and eventually low residual stress, leading to a homogeneous magnetic domain structure, as compared to the inhomogeneous “fingerprint-like” complex domains in highly magnetostrictive CoFe-rich alloys.

Place, publisher, year, edition, pages
Elsevier B.V., 2021
Keywords
Amorphous alloys, Eddy current loss, Excess loss, High-frequency applications, Materials loss mechanisms, Soft magnetic materials, Ultra-thin ribbons, Amorphous materials, Cobalt alloys, Domain walls, Eddy current testing, Iron alloys, Magnetic domains, Magnetic materials, Magnetostriction, Nanocrystalline alloys, Saturation magnetization, Broad frequency range, Co-rich amorphous alloys, Domain wall displacement, Magnetization reversal mechanisms, Minor hysteresis loop, Remanent magnetization, Saturation magnetostriction, Ultra high performance, Magnetization reversal
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-290265 (URN)10.1016/j.jmmm.2020.167469 (DOI)000672633100006 ()2-s2.0-85093650280 (Scopus ID)
Note

QC 20210319

Available from: 2021-03-19 Created: 2021-03-19 Last updated: 2022-06-25Bibliographically approved
Huang, S., Dong, Z., Mu, W., Ström, V., Chai, G., Varga, L. K., . . . Vitos, L. (2021). Magnetocaloric properties of melt-spun MnFe-rich high-entropy alloy. Applied Physics Letters, 119(14), Article ID 141909.
Open this publication in new window or tab >>Magnetocaloric properties of melt-spun MnFe-rich high-entropy alloy
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2021 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 119, no 14, article id 141909Article in journal (Refereed) Published
Abstract [en]

High-entropy functional materials are of great interest in materials science and engineering community. In this work, ab initio electronic structure calculations of the phase stability and magnetic transition temperature of AlxCr0.25MnFeCo0.25-yNiy (x = 0-0.5, y = 0-0.25) alloys were performed to screen for compositions showing promising magnetocaloric properties in the vicinity of room temperature. The selected Al0.44Cr0.25MnFeCo0.05Ni0.2 alloy was synthesized via a rapid solidification technique and systematically characterized with respect to its structural and magnetocaloric properties. The results indicate that this alloy possesses a homogeneous microstructure based on an underlying body-centered cubic lattice and has a Curie temperature of & SIM;340 K. The temperature dependence of the adiabatic temperature change was evaluated using both direct and indirect methods. The ab initio-assisted design of 3d-metal-based high-entropy alloys, explored here, is intended to contribute to the development of magnetic refrigerators for room-temperature applications.

Place, publisher, year, edition, pages
AIP Publishing, 2021
National Category
Condensed Matter Physics Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-307561 (URN)10.1063/5.0065067 (DOI)000725036000006 ()2-s2.0-85116859996 (Scopus ID)
Note

QC 20220131

Available from: 2022-01-31 Created: 2022-01-31 Last updated: 2022-06-25Bibliographically approved
Dong, Z., Huang, S., Ström, V., Chai, G., Varga, L. K., Eriksson, O. & Vitos, L. (2021). MnxCr0.3Fe0.5Co0.2Ni0.5Al0.3 high entropy alloys for magnetocaloric refrigeration near room temperature. Journal of Materials Science & Technology, 79, 15-20
Open this publication in new window or tab >>MnxCr0.3Fe0.5Co0.2Ni0.5Al0.3 high entropy alloys for magnetocaloric refrigeration near room temperature
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2021 (English)In: Journal of Materials Science & Technology, ISSN 1005-0302, Vol. 79, p. 15-20Article in journal (Refereed) Published
Abstract [en]

High entropy alloys (HEAs) based on transition metals display rich magnetic characteristics, however attempts on their application in energy efficient technologies remain scarce. Here, we explore the magnetocaloric application for a series of MnxCr0.3Fe0.5Co0.2Ni0.5Al0.3 (0.8 < x < 1.1) HEAs by integrated theoretical and experimental methods. Both theory and experiment indicate the designed HEAs have the Curie temperature close to room temperature and is tunable with Mn concentration. A non-monotonic evolution is observed for both the entropy change and the relative cooling power with changing Mn concentration. The underlying atomic mechanism is found to primarily emerge from the complex impact of Mn on magnetism. Advanced magnetocaloric properties can be achieved by tuning Mn concentration in combination with controlling structural phase stability for the designed HEAs. 

Place, publisher, year, edition, pages
Chinese Society of Metals, 2021
Keywords
Experiment and Ab initio, High entropy alloys, Magnetic phase transition, Magnetocaloric materials, Aluminum alloys, Chromium alloys, Cobalt alloys, Energy efficiency, Entropy, High-entropy alloys, Iron alloys, Manganese, Energy efficient technology, Experimental methods, Magnetic characteristic, Magnetocaloric properties, Mn concentrations, Near room temperature, Relative cooling power, Structural phase stability, Manganese alloys
National Category
Condensed Matter Physics Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-292511 (URN)10.1016/j.jmst.2020.10.071 (DOI)000654379000002 ()2-s2.0-85098116535 (Scopus ID)
Note

QC 20210412

Available from: 2021-04-12 Created: 2021-04-12 Last updated: 2024-01-09Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2170-0076

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