Pressure-induced magnetic and valence transition in YbMn 2Ge 2

Abstract

The effect of applied pressure on the valence and magnetic properties of YbMn 2Ge 2 (tetragonal ThCr 2Si 2-type structure; I4/mmm) has been investigated by neutron powder diffraction measurements over the temperature range ∼1.5–300 K. Concurrent with a strong decrease in unit cell volume (∼−7%), the magnetic ordering scheme of YbMn 2Ge 2 is found to change significantly from a predominately planar antiferromagnetic arrangement at ambient temperature and pressure to a collinear antiferromagnetic structure around p ∼1.5 Gpa.