Journal ArticleDOI
On the relationship of high coercivity and L10 ordered phase in CoPt and FePt thin films
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TLDR
In this paper, the microstructure and the room-temperature hysteretic magnetic properties of sputtered, 10 nm thin films of equiatomic binary alloys of CoPt and FePt were characterized using transmission electron microscopy (TEM) and a superconducting quantum interference device (SQUID) magnetometer.Abstract:
The microstructure and the room-temperature hysteretic magnetic properties of sputtered, 10 nm thin films of equiatomic binary alloys of CoPt and FePt were characterized using transmission electron microscopy (TEM) and a superconducting quantum interference device (SQUID) magnetometer. A transformation from an atomically disordered, face-centered-cubic structure to the L10 ordered structure occurred during postdeposition annealing and was characterized using digital analysis of dark-field TEM images. The transformation was observed to follow first-order nucleation and growth kinetics, and the ordered volume fraction transformed was quantified at numerous points during the transformation. The ordered volume fraction was then compared to the magnetic coercivity data obtained from the SQUID magnetometer. In contrast to the relationship most commonly described in the literature, that the highest coercivity corresponds to a two phase ordered/disordered mixture, the maximum value for coercivity in this study wa...read more
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Journal ArticleDOI
Monodisperse FePt Nanoparticles and Ferromagnetic FePt Nanocrystal Superlattices
TL;DR: Thermal annealing converts the internal particle structure from a chemically disordered face- centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies that can support high-density magnetization reversal transitions.
Journal ArticleDOI
Recent Advances in Chemical Synthesis, Self‐Assembly, and Applications of FePt Nanoparticles
TL;DR: In this paper, a review of recent advances in chemical synthesis, self-assembly, and potential applications of monodisperse binary FePt nanoparticles is presented. And the surface, structural, and magnetic properties of these nanoparticles are discussed, along with three potential applications in data storage, permanent magnetic nanocomposites, and biomedicine.
Journal ArticleDOI
Size‐Dependent Chemical and Magnetic Ordering in L10‐FePt Nanoparticles
Chuanbing Rong,Daren Li,Vikas Nandwana,Narayan Poudyal,Yong Ding,Zhong Lin Wang,Hao Zeng,J. P. Liu +7 more
TL;DR: In this paper, the size dependence of the chemical ordering parameter S and selected magnetic properties of the L10-FePt phase has been investigated, including the Curie temperature, Tc, magnetization, etc.
Journal ArticleDOI
Phase Transformation, Coalescence, and Twinning of Monodisperse FePt Nanocrystals
TL;DR: The phase transformation, coalescence, and twin structure of thermally annealed 6 nm FePt nanocrystals under high vacuum on an amorphous carbon surface have been investigated in this article.
Journal ArticleDOI
Hard-Magnet L10-CoPt Nanoparticles Advance Fuel Cell Catalysis
Junrui Li,Shubham Sharma,Xiaoming Liu,Yung Tin Pan,Jacob S. Spendelow,Miaofang Chi,Yukai Jia,Peng Zhang,David A. Cullen,Zheng Xi,Honghong Lin,Zhouyang Yin,Bo Shen,Michelle Muzzio,Chao Yu,Yu Seung Kim,Andrew A. Peterson,Karren L. More,Huiyuan Zhu,Shouheng Sun +19 more
TL;DR: In this article, a hard-magnet core/shell L10-CoPt/Pt nanoparticles with 2-3 atomic layers of strained Pt shell was synthesized for ORR.
References
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Book
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TL;DR: In this paper, the authors present materials at the practical rather than theoretical level, allowing for a physical, quantitative, measurement-based understanding of magnetism among readers, be they professional engineers or graduate-level students.
Journal ArticleDOI
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TL;DR: In this paper, the authors report the preparation, microstructural characterization, magnetic properties, and magnetic recording performance of L1/sub 0/ phase thin (25 /spl Aring/ to 200 /spl Ring/) films, which are prepared by sputter deposition and ex-situ anneal.
Journal ArticleDOI
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TL;DR: In this paper, the authors reviewed magnetization reversal and factors determining coercivity for various permanent magnet materials. But they did not consider the effect of magnetization reversals on magnetization.
Journal ArticleDOI
Magnetic properties and structure of cobalt-platinum thin films
TL;DR: The magnetic properties of RF sputtered Co-Pt alloy thin films were studied as a function of Pt content from 0 to 80 at%. At room temperature, ferromagnetic films were obtained in the range 0-32 and 40-80 at% Pt; discontinuities in the magnetization, magnetostriction and coercivity versus Pt content were observed; however no discontinuity was observed in the resistivity as mentioned in this paper.
Journal ArticleDOI
The magnetic properties of platinum cobalt near the equiatomic composition part I. the experimental data
R. A. McCurrie,P. Gaunt +1 more
TL;DR: In this article, a single crystal disc of a Pt 52 at. % Co alloy has been prepared and magnetization and crystalline anisotropy measurements have been carried out with the specimen in the disordered cubic and in the ordered tetragonal phase.