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High Entropy Materials With Strong Magnetic Anisotropy

Record Type:	Language materials, printed : Monograph/item
Title/Author:	High Entropy Materials With Strong Magnetic Anisotropy/ Willie Brookings Beeson.
Author:	Beeson, Willie Brookings,
Description:	1 electronic resource (169 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 86-12, Section: B.
Contained By:	Dissertations Abstracts International86-12B.
Subject:	Materials science. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31995178
ISBN:	9798315793960

High Entropy Materials With Strong Magnetic Anisotropy
Beeson, Willie Brookings,

High Entropy Materials With Strong Magnetic Anisotropy [eletronic resource] /Willie Brookings Beeson. - 1 electronic resource (169 pages)

Source: Dissertations Abstracts International, Volume: 86-12, Section: B.

The development of high magnetic anisotropy materials that are easily manufacturable is essential for progress in magnetic recording, spintronics, and permanent magnets, impacting numerous industry sectors. Current high anisotropy alloys rely on rare-earth metals which pose serious sustainability risks, leaving a pressing need for discovery of new high anisotropy materials using earth-abundant elements, while the pool of binary and ternary alloys has been largely exhausted. My research explores the high entropy alloy (HEA) phase space for discovery of novel rare-earth-free materials with high magnetic anisotropy. HEAs comprising five or more elements achieve stable single-phase structures by virtue of their configurational entropy, opening a vast arena for discovery of new functional materials. While HEA literature largely focuses on mechanically robust but chemically disordered cubic structures, my work targets design and fabrication strategies which facilitate ordered, low-symmetry phases for functional properties such as high magnetic anisotropy.This work demonstrates successful fabrication routes to single-phase HEA thin films based on sputtering with rapid thermal annealing (RTA). FeCoNiMnCu films treated with RTA show a single face-centered cubic phase and 40-fold increase in coercivity compared with the as-grown film, indicating significant strain-induced magnetic anisotropy which is not present in the bulk system. To facilitate reduced crystal symmetry, we introduce Pt to realize single-phase (FeCoNiMnCu)Pt films with a highly ordered L10 superlattice, high perpendicular anisotropy, and 3 order of magnitude coercivity increase after RTA. This technique is expanded to stabilize a C16 tetragonal structure in HEAs through the inclusion of boron (B). Using a combinatorial fabrication method, we map the properties across the composition space of (FexCoyNizMn1-x-y-z)₂B to discover novel boride compositions with high anisotropy facilitated through a unique tunability of the electronic structure. Finally, we investigate the magnetic order of chemically disordered HEA films, revealing an unexpected exchange bias effect and magnetic phase transition in sputtered FeCoNiMnAlx films mediated by non-magnetic Al addition. The results presented here illustrate the potential of HEAs as an emerging avenue for the development of novel and sustainable functional magnetic materials.

English

ISBN: 9798315793960Subjects--Topical Terms:

557839
Materials science.
Subjects--Index Terms:

High entropy materials

High Entropy Materials With Strong Magnetic Anisotropy
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520 # $a The development of high magnetic anisotropy materials that are easily manufacturable is essential for progress in magnetic recording, spintronics, and permanent magnets, impacting numerous industry sectors. Current high anisotropy alloys rely on rare-earth metals which pose serious sustainability risks, leaving a pressing need for discovery of new high anisotropy materials using earth-abundant elements, while the pool of binary and ternary alloys has been largely exhausted. My research explores the high entropy alloy (HEA) phase space for discovery of novel rare-earth-free materials with high magnetic anisotropy. HEAs comprising five or more elements achieve stable single-phase structures by virtue of their configurational entropy, opening a vast arena for discovery of new functional materials. While HEA literature largely focuses on mechanically robust but chemically disordered cubic structures, my work targets design and fabrication strategies which facilitate ordered, low-symmetry phases for functional properties such as high magnetic anisotropy.This work demonstrates successful fabrication routes to single-phase HEA thin films based on sputtering with rapid thermal annealing (RTA). FeCoNiMnCu films treated with RTA show a single face-centered cubic phase and 40-fold increase in coercivity compared with the as-grown film, indicating significant strain-induced magnetic anisotropy which is not present in the bulk system. To facilitate reduced crystal symmetry, we introduce Pt to realize single-phase (FeCoNiMnCu)Pt films with a highly ordered L10 superlattice, high perpendicular anisotropy, and 3 order of magnitude coercivity increase after RTA. This technique is expanded to stabilize a C16 tetragonal structure in HEAs through the inclusion of boron (B). Using a combinatorial fabrication method, we map the properties across the composition space of (FexCoyNizMn1-x-y-z)₂B to discover novel boride compositions with high anisotropy facilitated through a unique tunability of the electronic structure. Finally, we investigate the magnetic order of chemically disordered HEA films, revealing an unexpected exchange bias effect and magnetic phase transition in sputtered FeCoNiMnAlx films mediated by non-magnetic Al addition. The results presented here illustrate the potential of HEAs as an emerging avenue for the development of novel and sustainable functional magnetic materials.
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653 # # $a Magnetism
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