The magnetic phase diagram of (DyxY1-x)Mn2 alloys

The evolutin with temperature and concentration of the magnetic structure of the C15 Laves phase alloys (DyxY1-x)Mn2 has been studied using neutron powder diffraction, ac susceptibility and high field dc magnetisation techniques. The phase diagram can be divided into three principal regions: for x≤0.2, the magnetic behaviour is closely similar to YMn2, although for x=0.2 the Mn moment has decreased to about 2.0μB at 2 K. For x≥0.8, the DyMn2 magnetic structure is found, but at x=0.7 a second type of antiferromagnetic structure has developed. This coupling persists as short range correlation into a remarkably wide range of intermediate compositions (0.7>x≥0.3) where there is no long range magnetic order down to low temperatures. (orig.)