Objective: In this brief review, the importance of nanotechnology in developing novel
magnetic energy storage materials is discussed.
Method: The discussion covers recent patents on permanent magnetic materials and especially covers
processing of permanent magnets (rare-earth and rare-earth free magnets), importance of rare-earth
permanent magnets and necessity of rare-earth free permanent magnets. Magnetic energy storage materials
are those magnetic materials which exhibit very high energy product (BH)max (where B is the
magnetic induction in Gauss (G) whereas H is the applied magnetic field in Oersted (Oe)). (BH)max is
the direct measure of the ability of a magnetic material to store energy.
Result: In this context, processing of magnetic energy storage composite materials constituted by soft
and hard magnetic materials played a predominant role in achieving high (BH)max values due to the exchange
coupling phenomenon between the soft and hard magnetic phases within the composite. Magnetic
energy storage composites are normally composed of rare-earth magnetic materials as well as
rare-earth free magnetic materials.
Conclusion: Nanotechnology’s influence on the enhancement of energy product due to the exchange
coupling phenomenon is of great prominence and therefore discussed in this review.
Keywords: Coercive field, hard magnets, magnetic energy storage, maximum energy product, nanomaterials, permanent magnets,
rare-earth free magnets, rare earth magnets.
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