HfCo7-Based Rare-Earth-Free Permanent-Magnet Alloys

Authors

• Bhaskar Das, University of Nebraska-LincolnFollow
• Balamurugan Balamurugan, University of Nebraska-LincolnFollow
• Pankaj Kumar, Kendriya VidhyalayaFollow
• Ralph Skomski, University of Nebraska-LincolnFollow
• Shah R. Valloppilly, University of Nebraska-LincolnFollow
• Jeffrey E. Shield, Iowa State UniversityFollow
• Arti Kashyap, LMN Institute of Information TechnologyFollow
• David J. Sellmyer, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

7-2013

Citation

IEEE TRANSACTIONS ON MAGNETICS, VOL. 49, NO. 7, JULY 2013; DOI: 10.1109/TMAG.2013.2242856

Comments

Copyright 2013 IEEE. Used by permission.

Abstract

This study presents the structural and magnetic properties of melt-spun HfCo₇, HfCo_7-xFe_x (0.25 ≤ x ≤ 1), and HfCo₇Si_x (0.2 ≤ x ≤ 1.2) alloys. Appreciable permanent-magnet properties with a magnetocrystalline anisotropy of about 9.6–16.5 Mergs/cm³, a magnetic polarization J_s ≈ 7.2–10.6 kG, and coercivities H_c = 0.5–3.0 kOe were obtained by varying the composition of these alloys. Structural analysis reveals that the positions of x-ray diffraction peaks of HfCo₇ show good agreement with those corresponding to an orthorhombic structure having lattice parameters of about a = 4.719 Å, b = 4.278 Å, and c = 8.070 Å. Based on these results, a model crystal structure for HfCo₇ is developed and used to estimate the magnetic properties of HfCo₇ using density-functional calculations, which agree with the experimental results.