Advanced Magnetic Materials for Sensors, Power, and Multifunctional Applications: Nanoscale Magnetism and High Coercivity Materials
Sponsored by: TMS Functional Materials Division, TMS: Magnetic Materials Committee
Program Organizers: Daniel Salazar, BCMaterials; Alex Leary, NASA Glenn Research Center; Eric Theisen, Energy & Environmental Research Center; Huseyin Ucar, California Polytechnic University,Pomona; Yongmei Jin, Michigan Technological University

Thursday 8:30 AM
March 3, 2022
Room: 213B
Location: Anaheim Convention Center

Session Chair: Jose Maria Porro, BCMaterials

8:30 AM
Evolution of Magnetic Properties during the Post-annealing Process for the Sintered (NdLa)-(FeCo)-B Based Magnets: Wei Tang¹; Jing Wang¹; Kinjal Gandha¹; Xubo Liu¹; Kevin Dennis¹; Ikenna Nlebedim¹; Ryan Ott¹; Scott McCall²; David Parker³; Jun Cui⁴; ¹Ames Laboratory; ²Lawrence Livermore National Laboratory; ³Oak Ridge National Laboratory; ⁴Iowa State University
    Replacing critical elements (Nd and Pr) in the RE₂Fe₁₄B-type magnet with less critical elements (La or Ce) has been intensively studied in the past ten years. However, the magnetic properties of the sintered magnets containing La or Ce are still much lower than the theoretical values predicted from the intrinsic properties of the La/Ce₂Fe₁₄ phase. The magnetic properties of a magnet are predominantly governed by its microstructures, which are sensitive to fabrication processes. Here, we report our work on understanding the effect of annealing processes on the magnetic properties of the sintered (Nd_0.75La_0.25)_2.6Fe_11.9Co₂Ga_0.1B magnet. Multi-stage annealing between 580°C and 460°C with different dwelling times has a dramatic impact on the magnetic properties of the magnet. The highest H_c and (BH)_max achieved are 9 kOe and 32.4 MGOe, respectively.

8:50 AM  Invited
Metal-organic Magnets with Large Coercivity and Ordering Temperatures up to 242°C: Itziar Oyarzabal¹; Panagiota Perlepe²; Aaron Mailman³; Morgane Yquel²; Mikhail Platunov⁴; Iurii Dovgaliuk⁵; Mathieu Rouzières²; Philippe Negrier⁶; Denise Mondieig⁶; Elizaveta A Suturina⁷; Dourges Marie-Anne⁸; Sébastien Bonhommeau⁸; Rebecca A. Musgrave²; Kasper Pedersen²; Dmitry Chernyshov⁵; Fabrice Wilhelm⁴; Andrei Rogalev⁴; Corine Mathonière⁹; Rodolphe Clérac²; ; ¹BCMaterials - Ikerbasque; ²Centre de Recherche Paul Pascal; ³University of Jyväskylä; ⁴ESRF-The European Synchrotron; ⁵ESRF - Swiss-Norwegian Beamline; ⁶Laboratoire Ondes et Matière d'Aquitaine - CNRS / Univ. Bordeaux; ⁷University of Bath; ⁸ISM - CNRS / Univ. Bordeaux; ⁹ICMCB - CNRS / Univ. Bordeaux
    Magnets derived from inorganic materials (e.g., oxides, rare-earth–based, and intermetallic compounds) are key components of modern technological applications. Despite considerable success in a broad range of applications, these inorganic magnets suffer several drawbacks, including energetically expensive fabrication, limited availability of certain constituent elements, high density, and poor scope for chemical tunability. A promising design strategy for next-generation magnets relies on the versatile coordination chemistry of abundant metal ions and inexpensive organic ligands. Following this approach, we report the general, simple, and efficient synthesis of lightweight, molecule-based magnets by postsynthetic reduction of preassembled coordination networks that incorporate chromium metal ions and pyrazine building blocks. The resulting metal-organic ferrimagnets feature critical temperatures up to 242°C and a 7500-oersted room-temperature coercivity.

9:20 AM
Quantum-confined Charge Transfer that Enhances Magnetic Anisotropy in Lanthanum M-type Hexaferrites: Churna Bhandari¹; Durga Paudyal¹; ¹Ames Laboratory
    Iron-based hexaferrites are critical-element-free permanent magnet components of magnetic devices. Of particular interest is electron-doped M-type hexaferrite i.e., LaFe12O19(LaM) in which extra electrons introduced by lanthanum substitution of barium/strontium play a key role in up-lifting the magnetocrystalline anisotropy. We investigate the electronic structure of lanthanum hexaferrite using a localized density functional theory which reproduces semiconducting behavior and identifies the origin of the very large magnetocrystalline anisotropy. Localized charge transfer from lanthanum to the iron at the crystal’s 2a site produces a narrow 3dz2 valence band strongly locking the magnetization along the c-axis. The calculated uniaxial magnetic anisotropy energies from fully self-consistent calculations are nearly double the single-shot values, and agree well with available experiments. The chemical similarity of lanthanum to other rare earths suggests that LaM can host for other rare earths possessing non-trivial 4f electronic states for, e.g., microwave-optical quantum transduction.

9:40 AM
Additive Manufacturing of 3D Metallic Structures: An Environmental-friendly Way of Printing Cellulose-based Metallic Inks: Bosco Rodriguez¹; Daniel Salazar¹; D. Payno¹; Volodymyr Chernenko²; ¹BCMaterials; ²BCMaterials; Ikerbasque, Basque Foundation for Science
    Current engineering technologies demand the ability of obtaining 3D structures in a green and a cost-effective way. In this work, we developed original inks and implemented printing technique to print 3D metallic structures at room temperature using various metallic powders (including magnetic and magnetocaloric powders), and cellulose as matrix with water as dissolvent. The ink containing more than 85 wt.% of powder was elaborated by achieving an optimal viscosity whereby high maximum number of layers (250 layers reached) with highest printing resolution (0.5mm wall thickness) was obtained. The elaborated technological route of the treatment of printed structures included: (i) special heat treatments to dry printed structures so the polymer was removed by calcination followed by a sintering to get entirely metallic structure, and (ii) electrodeposition of nickel to protect printed structure from any corrosion. We also demonstrated that any incorrectly printed workpiece can be recycled re-dissolving it in the water so material loss is reduced significantly making the printing more cost-efficient and environmentally friendly.