A. Sundaresan: Coexistence of a- and c-axis polarizations and independent rare-earth-ordering-induced polarization in Gd0.5Dy 0.5MnO3
Magnetoelectric measurements on a single crystal of orthorhombic manganite, Gd0.5Dy0.5MnO3, reveal that the ferroelectric polarization along the a-axis coexists with a significant polarization along the c-axis. Unlike RMnO3 (R = Tb and Dy), this system exhibits a flop of ferroelectric polarization from a to c axis, when magnetic field is applied along the a-axis. Intriguingly, there is a large enhancement of Curie temperature and ferroelectric polarization along the a-axis when the magnetic field is applied along the b-axis. Further, below TNR = 6 K, the polarization along the a-axis decreases to almost zero, which seems to indicate that the magnetic ordering of R-ions destroys the polarization due to cycloidal spins of Mn ions. At the same time, the rare earth ordering induces polarization independently. In my talk, I shall compare and contrast these results with the other RMnO3 systems.