Substitution of Y for Pr in PrMn2Ge2-The magnetism of Pr0.8Y0.2Mn2Ge2

Pr0.8Y0.2Mn2 Ge 2 is found to exhibit four magnetic transitions on decreasing the temperature from the paramagnetic region: (i) paramagnetism to intralayer antiferromagnetism (AFl) at TN intra; (ii) AFl to canted ferromagnetism (Fmc) at TC inter; (iii) Fmc to conical magnetic ordering of the Mn sublattice (Fmi) at Tcc; and (iv) Fmi(Mn) to Fmi(Mn) + F(Pr) at TC Pr. These changes in magnetic structure are discussed in terms of changes in the Mn-Mn separation distances caused by the unit cell contraction and by electronic effects due to replacement of 20% of Pr with Y.