The influence of substitution of Co for Mn on magnetism of the HoMn6−xCoxSn6 compounds (0⩽x⩽0.25)

Abstract We have studied the effects of Co substitution for Mn on the structure and magnetic properties of the HoMn 6− x Co x Sn 6 compounds (0⩽ x ⩽0.25) with HfFe 6 Ge 6 -type structure (space group P6/mmm) by X-ray powder diffraction and magnetization measurements. A monotonic decrease of the lattice parameters a and c is observed with increasing Co content. While the compounds with x =0 and 0.05 exhibit ferrimagnetism in the whole temperature range, the compounds with 0.1⩽ x ⩽0.15 show ferrimagnetism, helimagnetism and re-entrant ferrimagnetism with decreasing temperature. For the compounds with x =0 and 0.05, the spin reorientation temperature is observed. A metamagnetic transition from helimagnetic magnetic ordering to ferrimagnetism is observed for the compounds with x =0.1 and 0.2. The results are summarized in the HoMn 6− x Co x Sn 6 magnetic phase diagram.