Abstract:
In Dy$_{1-x}$Ho$_x$MnO$_3$ single crystals with the orthorhombic space group Pbnm, ferroelectric hysteresis loops were measured for compositions with $x$ = 0 and 0.3. As the content of Ho$^{3+}$ ions increases, the hysteresis loop narrows and for $x$ = 0.3 it no longer manifests itself. An analysis of the signal corresponding to the hysteretic behavior of a ferroelectric showed that even harmonics can be obtained only if the hysteresis loop is not symmetric about the abscissa axis. In view of the latter, the hypothesis that the second harmonic of the magnetoelectric effect is a consequence of the complex dependence of the polarization on time due to its hysteresis becomes doubtful. Measurements of the dependence of the inverse magnetoelectric effect on the amplitude of the applied electric field $\Delta M(E)$ showed that the first harmonic remains linear with respect to the electric field even in the electric field strength region where the domain structure of the ferroelectric is rearranged.
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