Research Papers in Physics and Astronomy


Date of this Version



Applied Physics Letters 101, 122407 (2012);


Copyright 2012 American Institute of Physics. Used by permission.


We report HfCo7 nanoparticles with appreciable permanent-magnet properties (magnetocrystalline anisotropy K1≈10 Mergs/cm3, coercivity Hc ≈ 4.4 kOe, and magnetic polarization Js≈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 Js 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.

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