Uniaxial pressure dependencies of the phase transitions in GdMnO3

Abstract GdMnO 3 shows an incommensurate antiferromagnetic order below ≃ 42 K , transforms into a canted A-type antiferromagnet below ≃ 20 K , and for finite magnetic fields along the b -axis ferroelectric order occurs below ≃ 12 K . From high-resolution thermal expansion measurements along all three principal axes, we determine the uniaxial pressure dependencies of the various transition temperatures and discuss their correlation to changes of the magnetic exchange couplings in R MnO 3 ( R = La , … , Dy ) .