Manipulating the Magnetic Structure with Electric Fields in Multiferroic ${\mathrm{ErMn}}_2{\mathrm{O}}_5$

Based on measurements of soft x-ray magnetic diffraction under in situ applied electric field, we report on significant manipulation and exciting of commensurate magnetic order in multiferroic ${\mathrm{ErMn}}_2{\mathrm{O}}_5$. The induced magnetic scattering intensity arises at the commensurate magnetic Bragg position whereas the initial magnetic signal almost persists. We demonstrate the possibility to imprint a magnetic response function in ${\mathrm{ErMn}}_2{\mathrm{O}}_5$ by applying an electric field.

Figure 1

$\theta /2\theta$ scans of the ($\frac{1}{2}$, 0, $\frac{1}{4}$)-reflection of ${\mathrm{ErMn}}_2{\mathrm{O}}_5$ taken at the Mn $L_3$-edge at $T=34\mathrm{K}$ below the 2D to 1D-ICM phase transition (a) and above at $T=38.5\mathrm{K}$ (b) with $\pi$-polarized incident light. $\delta$ corresponds to the magnetic and $-2\delta$ to the induced aspheric charge reflection (see text). The inset show the intensity difference $\Delta I^{\pm }=I(\pm E)-I(0\mathrm{V})$.

Figure 2

(a) Temperature dependence of the magnetic ($\frac{1}{2}$, 0, $\frac{1}{4}$)-reflection and the incommensurate $\delta$ and $-2\delta$ reflections of ${\mathrm{ErMn}}_2{\mathrm{O}}_5$. $T_D=T_{C1}=39.1\mathrm{K}$ is defined by the change in slope of $\delta (T)$ and $-2\delta (T)$. At $T_{\mathrm{CM}}=37.7\mathrm{K}$, ${\mathrm{ErMn}}_2{\mathrm{O}}_5$ enters the CM. (b) Intensity difference $\Delta I(T)$ as function of temperature. The appearance of $\Delta I$ at $T_D$ is explicitly shown in Fig. 3c.

Figure 3

(a) X-ray intensity $I$ as function of temperature for the $\delta$ and $-2\delta$ satellites. (b) The temperature dependence of $I$ (solid line and dots) for $\delta$ follows a power law at low temperatures (dotted line). (c) $\Delta I(T)$ follows the polarization $P_b$ for $H=0\mathrm{T}$ (reproduced from Ref. 26). (d) X-ray intensity $I$ as function of the applied electric field at $T=38.5\mathrm{K}$, showing its hysteretic behavior after $\mathrm{FC}(+)$. The dotted line shows the bias field.