Temperature evolution of polar states in GdMn2O5 and Gd0.8Ce0.2Mn2O5
V. A. Sanina, E. I. Golovenchits, B. Kh. Khannanov, M. P. Scheglov, V. G. Zalesskii
Ioffe Physical Technical Institute of the RAS, 194021 S.Petersburg, Russia
Abstract
The polar order along the c axis is revealed in GdMn2O5 and
Gd0.8Ce0.2Mn2O5
at K for the first time. This polar order is
induced by the charge disproportion
in the 2D superstructures emerged due to phase separation. The dynamic state
with restricted polar domains of different sizes
is found at T > TC1 which is typical of the diffuse ferroelectric phase
transition.
At the lowest temperatures (T < 40 K) two polar orders of different
origins with perpendicular orientations (along the b- and c-axes) coexist.
The 1D superlattices studied by us earlier in the set of RMn2O5
multiferroics are the charged domain walls which separate of these polar order
domains.