Itinerant-electron metamagnetic transition and large magnetovolume effects inLa(FexSi1−x

Magnetic properties and magnetovolume effects have been investigated for itinerant-electron metamagnetic $\mathrm{La}({\mathrm{Fe}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}{)}_{13}$ compounds. At the Curie temperature ${T}_{C1},$ a first-order magnetic phase transition takes place in the concentration range $0.86<~x<~0.88.$ With increasing Fe concentration, the Curie temperature decreases and the critical temperature of the itinerant-electron metamagnetic (IEM) transition increases, accompanied by a more sharp IEM transition. For the compound with $x=0.88,$ a large volume change of about 1% follows the thermal induced transition at ${T}_{C1}.$ The value of ${T}_{C1}$ is significantly decreased by applying hydrostatic pressure, whereas the pressure dependence of the spontaneous magnetization is relatively small. These results are explained by the negative mode-mode coupling among spin fluctuations.