MAGNETIC-STRUCTURES OF ND2FE2SI2C AND TB2FE2SI2C

Magnetic properties of R2Fe2Si2C (with R = Nd, Tb) have been studied b y means of neutron diffraction. An antiferromagnetic behaviour have be en evidenced below 15K for the Nd based compound and 45 K for the Tb b ased compound. The magnetic cell is twice the crystallographic one, wi th a propagation vector k = (0, 0, 1/2). The main original feature of both structures is the non-colinearity between both R and Fe sublattic es, the magnetic moments being nearly perpendicular.