Uniaxial pressure dependencies of the phase transitions in GdMnO3

GdMnO3 shows an incommensurate antiferromagnetic order below similar or equal to 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 similar or equal to 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 RMnO3 (R = La,..., Dy). (c) 2006 Elsevier B.V. All rights reserved.