Permanent magnetic properties of rapidly quenched (La,Ce)2Fe14B nanomaterials based on La–Ce mischmetal

• The (La0.35Ce0.65)xFe14B ribbons were prepared by melt-spinning with mischmetal.
• The energy product of (La0.35Ce0.65)2Fe14B is twice lager than that of Ce2Fe14B.
• The second-phase appears when x = 3.6 and 4.0, which is La–Ce alloy but not CeFe2.
• The strong pinning effect dominate the magnetization reversal process.
• The evidence of the existence of exchange coupling interaction was found.

High performance (La0.35Ce0.65)xFe14B (x = 2.0, 2.4, 2.8, 3.2, 3.6, 4.0) ribbons were prepared by melt-spinning method, using industrial La–Ce mischmetal. Phase composition and room temperature permanent magnetic properties were investigated. The main phases of all samples crystallize in the tetragonal 2:14:1 type structure. A second-phase appears when x = 3.6 and 4.0, which is La–Ce alloy with a crystal structure of face-centered cubic but not CeFe2. Replacement of CeFe2 by La–Ce alloy enhances the temperature stability of the magnetic material at low temperature. The intrinsic coercivity increases with x monotonously, and the energy product reaches a maximal value of 8.29 MGOe at x = 2.4 when an optimal wheel velocity of 20 m/s was adopted, which is twice of that of Ce2Fe14B. The coercivity mechanism and intergrain exchange coupling were studied by using minor loops. The results indicated that strong pinning effect dominate the magnetization reversal process in all of the rare-earth-rich ribbons. The structure-property relationship was analyzed by using Henkel plots, and intergrian exchange coupling were found in all samples.

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