1. LaFeSi–LaFe13−xSix composites: Modulating magnetic and magnetocaloric properties through inherent stress manipulation.
- Author
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Del Rose, Tyler J., Chouhan, Rajiv K., Doyle, Andrew, Pathak, Arjun K., and Mudryk, Yaroslav
- Subjects
MAGNETIC transitions ,MAGNETIC properties ,FIRST-order phase transitions ,MAGNETIC fields ,TEMPERATURE control ,MAGNETIC entropy - Abstract
We examine structural and magnetic properties of a series of La–Fe–Si alloys in the region of concentrations where they naturally form two-phase LaFeSi–LaFe
13−x Six composites with variable content and connectivity of LaFe13−x Six grains distributed within the LaFeSi matrix. Theoretical calculations confirm that the LaFeSi constituent is magnetically and structurally inert below room temperature and at pressures between −10 and 10 GPa. The LaFe13−x Six constituent, on the other hand, is magnetically and structurally active: it exhibits first-order magnetostructural transformations that, in addition to xSi , can be controlled with temperature, magnetic field, and pressure. In composites where the concentration of the inactive constituent is ∼70 wt. % or greater, the standard, single-step, LaFe13−x Six first-order phase transformation proceeds in two steps separated by over 30 K in a zero magnetic field. Increasing the magnetic field recouples the two steps and restores the single-step phase transformation pathway. We analyze the roles of stresses caused by both thermal expansion mismatch and the first-order magnetic phase transition in LaFe13−x Six to rationalize the observed physical behaviors that emerge as the temperature or/and magnetic field vary. [ABSTRACT FROM AUTHOR]- Published
- 2024
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