The (T,x) magnetic phase diagram of TbNi Ge2 (0.4<x<1) compounds. A neutron study

The magnetic structure of the TbNixGe2 (x=0.8, 0.6) compounds has been studied by neutron powder diffraction. The paramagnetic neutron data confirmed the CeNiSi2 type of structure reported earlier for this compound. The magnetic ordering is associated with the wave vector q1=0 over the entire magnetically ordered regime for both compounds. The Tb moments adopt a uniaxial antiferromagnetic arrangement (Gz mode) with c as the preferred axis, invariant under the magnetic space group C 2 m′ 2′ c 2 1 ′ m similar to the x=0.4 and 1.0 compounds. At 1.5 K the refined moment values are: μTb=8.7(1)μB for x=0.8 and 8.9(1)μB for x=0.6. The (T,x) magnetic phase diagram indicates that TN increases linearly with increasing Ni content (31–42 K) in the 0.6