Giant volume magnetostriction in La0.85Ce0.15Fe12B6
Résumé
We report the discovery of giant magnetostriction and huge negative thermal expansion (NTE) in the itinerant-electron metamagnetic compound La0.85Ce0.15Fe12B6. This system presents multiple magnetic transformations, antiferromagnetic-ferromagnetic (AFM-FM) and ferromagnetic-paramagnetic (FM-PM), driven by changes in both external field and temperature. The magnetic-field-dependent magnetostriction exhibits irreversible abrupt jumps at T ≤ 5 K, while it evolves smoothly with applied field above 5 K. A giant positive volume magnetostriction of DV/V (20 K, 6 T) = 0.80% is observed across the field-induced first-order AFM-FM metamagnetic transition. It is further revealed that the FM-PM transition is accompanied by a remarkably large NTE with a coefficient of linear thermal expansion alphaL =-34×10-6 K-1 over a temperature window of ΔT ~ 63 K.
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