Magnetic properties of CeFeSi-type RTiSi compounds (R=Gd–Tm, Lu, Y) from magnetic measurements and neutron diffraction

Abstract Numerous solid-state syntheses clearly show that the CeFeSi-type (P4/nmm) RTiSi series is limited to the heaviest rare-earth elements (R=Gd–Tm, Lu, Y). Bulk magnetisation and neutron diffraction measurements have been performed on these compounds. YTiSi and LuTiSi are Pauli paramagnets whereas the R(=Gd–Tm)TiSi compounds behave antiferromagnetically below 400, 288, 175, 98, 51 and 20 K, respectively. The magnetic structure of the (Tb–Er)TiSi compounds consists of ferromagnetic (0 0 1) R layers antiferromagnetically coupled along the c -axis with the (++−−) coupling sequence. The three first compounds exhibit an easy-axis anisotropy whereas an easy plane prevails in ErTiSi. In all cases, the R moment value is close to the R 3+ value (gJ). The results are compared with those obtained on the corresponding RTiGe germanides.