Assembly of uniaxially aligned rare-earth-free nanomagnets

Authors

Balamurugan Balamurugan, University of Nebraska-LincolnFollow
Bhaskar Das, University of Nebraska-LincolnFollow
Shah R. Valloppilly, University of Nebraska-LincolnFollow
Ralph Skomski, University of Nebraska-LincolnFollow
Xingzhong Li, University of Nebraska-LincolnFollow
David J. Sellmyer, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2012

Citation

Applied Physics Letters 101, 122407 (2012); http://dx.doi.org/10.1063/1.4753950

Comments

Copyright 2012 American Institute of Physics. Used by permission.

Abstract

We report HfCo₇ nanoparticles with appreciable permanent-magnet properties (magnetocrystalline anisotropy K₁≈10 Mergs/cm³, coercivity H_c ≈ 4.4 kOe, and magnetic polarization J_s≈10.9 kG at 300 K) deposited by a single-step cluster-deposition method. The direct crystalline-ordering of nanoparticles during the gas-aggregation process, without the requirement of a high-temperature thermal annealing, provides an unique opportunity to align their easy axes uniaxially by applying a magnetic field of about 5 kOe prior to deposition, and subsequently to fabricate exchange-coupled nanocomposites having J_s as high as 16.6 kG by co-depositing soft magnetic Fe-Co. This study suggests HfCo₇ as a promising rare-earth-free permanent-magnet alloy, which is important for mitigating the critical-materials aspects of rare-earth elements.