  The ternary intermetallic compound Pr6Ni2Si3, is a member of a structure
series of compounds based on a triangular structure where the number of Pr
atoms in the prism cross section can be systematically varied. Pr6Ni2Si3
contains two distinct Pr lattice sites which result in complex interactions
between the magnetic ions. Extensive measurements of specific heat and
magnetization on single crystal samples indicate that Pr6Ni2Si3 orders with
both a ferromagnet and an antiferromagnet component, with ordering temperatures
of 39.6 K and ~ 32 K, respectively. The ferromagnetic component // c-axis is
accompanied by a large hysteresis, and the antiferromagnetic component,_|_
c-axis is accompanied by a spin-flop-type transition. More detailed
measurements, of the vector magnetization, indicate that the ferromagnetic and
the antiferromagnetic order appear independent of each other. These results not
only clarify the behavior of Pr6Ni2Si3 itself, but also of the other members of
the structure series, Pr5Ni2Si3 and Pr15Ni7Si10.
