Structure and magnetic properties of RAlSi(R=light rare earth)

We prepared the semimetals RAl Si(R=light rare earth),and systematically study their crystal structures and magnetic properties.X-ray diffractions confirm the coexistence of the site-disordered phase with group space of I41/amd and the noncentrosymmetrically ordered phase with space group of I41 md in RAl Si alloy.The ordered phase is the main phase in RAl Si alloy.RAl Si alloys show nonmagnetic character for R=La,low temperature ferromagnetic order for R=Ce,Pr,and paramagnetic character for R=Nd,respectively.Sm Al Si shows metamagnetic transition at 10 K and ferromagnetic order at 143 K,respectively.Sm Al Si follows the van Vleck paramagnetic model in its paramagnetic region.The magnetization curves of RAl Si(R=Ce,Pr,Sm)follow the mixed model of ferromagnetism and paramagnetism,and the fitted saturation moment MSdepends on the moment of trivalent rare earth.The paramagnetic susceptibilityχof RAl Si is going up with increasing the atomic order numbers of rare earth elements.This reveals that the magnetic property of RAl Si originates from the rare earth.