Exotic (anti)ferromagnetism in single crystals of Pr6Ni2Si3
  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. 
Y. Janssen, K. W. Dennis, R. Prozorov, P. C. Canfield, R. W. McCallum