Improvement of the double-wave method for ferroelectric hysteresis loops and its application to multiferroic euMn₂O₅

We measured the ferroelectric D-E hysteresis loops of multiferroic EuMn₂O₅ by using the doublewave method (DWM), which was recently developed. The DWM can extract the hysteresis loops with respect to the bias electric field, for example, ferroelectric loops and antiferroelectric loops. Improvements and supplementary explanations for the DWM are given in this paper. Ferrielectric hysteresis loops were obtained as combinations of three loops by using the non-biased and biased DWM. The temperature dependences of the ferroelectric and the antiferroelectric parts of the polarization of EuMn ₂O₅ was measured by using the DWM. The former decreases and the latter increases between about 14 - 21 K.