Magnetics and the Critical Materials Challenge: An FMD Symposium Honoring Matthew J. Kramer: The Softer Side of Magnetism
Sponsored by: TMS Functional Materials Division, TMS: Magnetic Materials Committee
Program Organizers: Scott McCall, Lawrence Livermore National Laboratory; Ryan Ott, Ames Laboratory

Tuesday 8:00 AM
March 1, 2022
Room: 210D
Location: Anaheim Convention Center

Session Chair: Scott McCall, LLNL

8:00 AM  Invited
Giant Saturation Magnetization of Fe-based Soft Magnetic Amorphous Alloy by Introducing Nitrogen: Song-Yi Kim1; Hye-Ryeong Oh2; Hwi-Jun Kim1; Min-Ha Lee3; 1KITECH; 2Korea Electronics Technology Institute; 3KITECH North America
    Transition metal nitrides have attracted great attention in recent years because of their outstanding physical and chemical characteristics, including optical, electrical, magnetic and mechanical properties. Commonly nitrogen introduced into magnetic materials as nitride forms, such as FeN, Co(Ni)N and (LiFe)N, which has strict limitation of chemical stoichiometry and crystal structure. In particular, iron nitrides to achieve non-rare earths based high performance magnetic characteristics have widely used as magnetic, optical recording materials. An excess Gibbs free energies induced and stored by non-equilibrium defects can provide extra driving force for nitride formation. The extra driving force stored in the Fe-based amorphous structure promotes occurring of nitridation. In the current study, we evaluate the role of nitrogen in enhancing magnetic moment of Fe-based amorphous alloy and raising Curie temperature which never been explored before.

8:30 AM  Invited
Nanocomposite Soft Magnetics: Applications, State-of-art, and Emerging Trends: Paul Ohodnicki1; 1University of Pittsburgh
    Numerous emerging trends are driving needs for advanced soft magnetic materials and devices including rapid deployment of renewables within the electric power grid and electrification of the transportation sector. Amorphous and nanocrystalline soft magnetic alloys have emerged as a premier solution for many of these applications including high-speed motors as well as medium frequency transformers and inductors for emerging power electronics-based converters. This presentation will provide an overview of recent developments in the field, inclusive of emerging alloy chemistries and advanced manufacturing approaches as well as device level applications. High potential areas for new research directions moving into the future will also be discussed, with particular emphasis on the perspective of optimal nanocrystalline alloy / device integration for improvements in key figures of merit such as size, weight, efficiency, and thermal performance. Broader needs for workforce development in advanced magnetic materials and devices for power applications will also be addressed.

9:00 AM  Invited
Like Poles Attraction and Unlike Poles Repulsion - Science Behind the Mystery: Hui Meng1; Guiping Tang2; Abby Shen3; Michelle Qian3; Qifeng Wei1; George Mizzell4; Min Zou3; Christina Chen3; 1Foresee Group; 2Quadrant at Hangzhou; 3Quadrant at San Jose; 4SuperMagnetMan
    Force between magnet pairs and surface flux density are studied to understand the attraction between magnetic like poles and repulsion between unlike poles with different permeance coefficients (Pc) and B-H characteristics. The magnet with a higher Pc can locally demagnetize the one with a lower Pc. A large localized demagnetization (LD) field can reverse the magnetic polarity in a localized region of the lower Pc magnet, resulting in attraction between the like poles. For magnets with nonlinear B-H curve in the 2nd quadrant, a repulsion can occur for the unlike poles after previously paired with their like poles. An inflection point (IP) was observed in every measured force vs gap distance curve for unequally sized pairs. The interactions of the IP, LD, and B-H linearity lead to diverse local magnetization states in unequally sized magnet pairs, which may be used to innovate novel magnetic components and devices.

9:30 AM Break

9:50 AM  Invited
Microstructural Evolutions, Phase Transformations and Hard Magnetic Properties in Polycrystalline Ce-Co-Fe-Cu Alloys: Kinjal Gandha1; Rakesh Chaudhary1; Matthew Kramer1; Ryan Ott1; Durga Paudyal1; Ikenna Nlebedim1; 1Ames Laboratory
    Developing alternatives/substitutes is an approach for addressing the challenges with sustainability in the supply of rare-earth-elements (REEs) for permanent magnets. Substantial efforts have been invested in Ce-based alloys as alternatives to magnets based on other critical REEs such as Nd, Pr, Dy and Sm (where applications allow). This presentation will include phase, microstructure and magnetic properties evolution in CeCo4.4-xFexCu0.6 and CeCo3.9-xFexCu1.2 (x=0-1.8). It will bridge the knowledge gap on how the constituent elements influence microstructural evolutions and the interaction between the competing phases (particularly near phase boundaries) and the functionality of the alloys as magnets. In both systems, the composition 0.6<x≥0.9 is near the boundary of solubility where other phase evolve, in addition to the 1:5 phase. We will present our systematic result on the phase evolutions with Fe and Cu contents and how the hard-magnetic properties respond. For example, increased Cu content enhanced coercivity to nearly 10kOe.

10:20 AM  Invited
Structure and Magnetic Properties of Galfenol Nanocomposite Alloys: M. T. Islam1; R. Nandwana1; J. Healy1; J. K. Jaklich1; B. Dong1; Matthew Willard1; A. Yu2; Y. Ijiri2; E. E. Moore3; S. K. McCall3; 1Case Western Reserve University; 2Oberlin College; 3Lawrence Livermore Laboratory
     The iron-rich alloy Galfenol (Fe1-x-Gax, 10%<x<30%) has been of significant interest for sensor technologies due to the sizeable magnetostriction coefficient found in single-crystal and polycrystalline films. [1,2] However, it is necessary to improve the magnetic softness of the material for many applications. To do so, we have explored the use of Zr and other glass formers and additives, rapid solidification approaches, and subsequent annealing to produce a nanocrystalline (Fe,Ga)-based alloy with the desired magnetostrictive and structural properties. We report studies on a series of 11 melt-spun and annealed (Fe1-x-Gax)92Zr8 alloy ribbons where the Ga concentration (0.15 ≤ x ≤ 0.36) by x-ray diffractometry, scanning electron microscopy, and magnetometry. As x exceeds 26 the formation of the ternary ZrFe6Ga6 intermetallic is observed, consistent with CALPHAD-type database calculations. Saturation magnetization, coercivity, and magnetostriction will also be reported in the context of structure-property relationships. Acknowledgment: Prepared by LLNL under Contract DE-AC52-07NA2.

10:50 AM  
A Solution to the Permalloy Problem: A. Renuka Balakrishna1; 1University of Southern California
    In 1914, a magnetic alloy with an unusually high magnetic permeability and low hysteresis was discovered at the Bell Telephone Laboratories. This magnetic alloy resulted from a series of investigations on the iron-nickel alloy system, in which the nickel content was systematically varied. Under a very specific combination of the alloy composition (78.5% Ni-content), a drastic increase in magnetic permeability and a decrease in coercive force were observed. In the past, this unusual behavior of the permalloy has been attributed to the anisotropy constant, however, there is still no theory that explains this drastic decrease in hysteresis in magnetic alloys. In today's talk, I will show how magnetostriction constants, in addition to anisotropy, play a surprisingly important role in reducing hysteresis at the permalloy composition. Our results demonstrate agreement with the permalloy experiments and provide theoretical insights into developing magnetic alloys with negligible hysteresis.