Magnetic ordering of the Pr sublattice with the substitution of Cu for Mn inPrMn2Si2 intermetallics

Abstract

The magnetic properties of PrMn2−xCuxSi2 () were studied by field-cooled and zero-field-cooled magnetization measurements in thetemperature range 5 K K in low external fields (5 mT) and by magnetic-field-dependent magnetization measurementsin fields up to 5.5 T. Substitution of Cu for Mn leads to a linear decrease in the lattice constantc and the unitcell volume V and a linear increase in the lattice constanta. Earlier neutron diffraction experiments showed that Pr does not order down to 1.6 K inPrMn2Si2 while the ferromagnetic Mn planes are ordered antiparallel along thec axis. With the increasing Cu content, the magnetization increases rapidly at lowtemperatures for the samples with . Cu substitution strongly changes the magnetic properties and leads to the magneticordering of the Pr sublattice. This is mainly deduced from the discussion of the valuesof the magnetic moments at low temperatures. Below the Curie temperaturesTC, the spins in the Mn sublattice are arranged parallel to the Pr sublattice. With increasing Cu,TC(x) has a maximumvalue of 155 K at x = 0.6 and decreases for samples with .