Magnetic properties of PrMn1.2Fe0.8Ge2

Abstract

As part of our investigation of the PrMn2-xFexGe2 series we have investigated the magnetic structures of PrMn1.2Fe0.8Ge2 (space group I4/mmm) by powder neutron diffraction and magnetic measurements. The Mn moments in PrMn1.2Fe0.8Ge2 exhibit only antiferromagnetic ordering whereas for lower Fe concentrations, x≤0.6, the Mn-sublattice exhibits ferromagnetic ordering. Two magnetic phase transitions take place with decreasing temperature in PrMn1.2Fe0.8Ge2. The first transition from paramagnetism to intralayer antiferromagnetic order (AFl) within the (0 0 1) Mn layers occurs at TN intra∼242 K. The second transition occurs at TN inter∼154 K; this transition is related to the change from the intralayer antiferromagnetic state to the antiferromagnetic mixed commensurate magnetic structure (AFmc). The neutron data also reveal an anisotropic thermal expansion within the interplanar antiferromagnetic region (-0.39% in the a-axis and+0.25% in the c-axis from∼160 to 3 K). © 2006 Elsevier B.V.