Magnetic ordering of the Pr sublattice with the substitution of Cu for Mn in PrMn2Si2 intermetallics

The magnetic properties of PrMn2−xCuxSi2 () were studied by field-cooled and zero-field-cooled magnetization measurements in the temperature range 5 K K in low external fields (5 mT) and by magnetic-field-dependent magnetization measurements in fields up to 5.5 T. Substitution of Cu for Mn leads to a linear decrease in the lattice constant c and the unit cell volume V and a linear increase in the lattice constant a. Earlier neutron diffraction experiments showed that Pr does not order down to 1.6 K in PrMn2Si2 while the ferromagnetic Mn planes are ordered antiparallel along the c axis. With the increasing Cu content, the magnetization increases rapidly at low temperatures for the samples with . Cu substitution strongly changes the magnetic properties and leads to the magnetic ordering of the Pr sublattice. This is mainly deduced from the discussion of the values of the magnetic moments at low temperatures. Below the Curie temperatures TC, the spins in the Mn sublattice are arranged parallel to the Pr sublattice. With increasing Cu, TC(x) has a maximum value of 155 K at x = 0.6 and decreases for samples with .