Magnetic-field-induced switching between ferroelectric phases in orthorhombic-distortion-controlled RMnO3

Abstract

We have investigated the dielectric and magnetic properties of Eu 0.595 Y 0.405 MnO 3 without the presence of the 4f magnetic moments of the rare earth ions, and have found two ferroelectric phases with polarization along the a and c axes in a zero magnetic field. A magnetic field induced switching from one to the other ferroelectric phase took plase in which the direction of ferroelectric polarization changed from the a axis to the c axis by the application of magnetic fields parallel to the a axis. In contrast to the case of TbMnO 3 , in which the 4f moments of Tb 3+ ions play an important role in such a ferroelectric phase switching, the magnetic-field-induced switching between ferroelectric phases in Eu 0.595 Y 0.405 MnO 3 does not originate from the magnetic transition of the rare-earth 4f moments, but from that of the Mn 3d spins.

Spin-Driven Ferroelectricity and Magneto-Electric Effects in Frustrated Magnetic Systems

“…[77][78][79][80] For another example, the electric polarization in (Eu,Y)-MnO 3 is rotated from along the a-axis to along the c-axis in a magnetic field along the a-axis, which stabilizes the spin helix on the bc plane. 81) This magnetic-field response is completely consistent with the prediction. By contrast, the changes in electric polariation of rare-earth orthomanganites GdMnO 3 , TbMnO 3 , and DyMnO 3 with external magnetic fields are complicated and apparently inconsistent with the theory.…”

Relaxor behavior in multiferroic BiMn2O5 ceramics

“…A freezing temperature of the polar nanoregions T f ¼ 512 K has been determined. This high temperature ferroelectric behavior is attributed to the Bi 3þ in the distorted BiO 8 cage. In RMn 2 O 5 (R ¼ Y, Er, Tm, Tb, Gd, Dy, Ho, and Bi), the coupling between the ferroelectric and antiferromagnetic phases, with the Néel temperature (T N ¼ 40 K), and the ability of a magnetic field to change the electric polarization have been extensively studied using different techniques.…”

“…We have assumed a connection between polarization and magnetic order from the data obtained from the pyroelectric coefficient measured until room temperature, but the true paramagnetic behavior starts around 250 K and the dielectric constant measurements have shown a relaxor behavior with a freezing temperature T f ¼ 512 K. Since there is no more magnetic order at these temperatures, a possible origin of this behavior comes from the BiO 8 45 have reported a room temperature pyroelectric coefficient value of 0.9 Â 10 À4 C/m 2 K. For the same samples, they have observed at room temperature (P-E) hysteresis loops (electric field up to 1500 V/cm) with remnant values of polarizations up to 13.2 lC/cm 2 . The sample quality seems to be of fundamental importance to make possible the observation of all the ferroelectric characteristics.…”

Landau model for the phase diagrams of the orthorhombic rare-earth manganitesRMnO3(R=Eu, Gd, Tb, Dy, Ho)

“…This geometric effect can be controlled either in a stepwise manner, by using rare-earth elements with different ionic radius (from R=La 3+ to Pr 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Yb 3+ and Lu 3+ ), or quasicontinuously, by tuning the average rare-earth radius in solid solutions in which the R 3+ ion is partially replaced by one isoelectric ion with different ionic radius, as in the case of the Eu 1-x Y x MnO 3 mixed system. [52][53][54][55] In the following we will analyze these two cases within the scope of the model presented above, as illustrative examples.…”