Polar and magnetic properties of $\mathrm{Pb}\mathrm{V}{\mathrm{O}}_3$ thin films

Multifunctional materials promise to provide the foundation for a class of devices in which electrical, magnetic, elastic, and other properties are coupled to one another. Here we present evidence for piezoelectricity and antiferromagnetic ordering in a multifunctional material $\mathrm{Pb}\mathrm{V}{\mathrm{O}}_3$. Through the use of second-harmonic generation and x-ray linear dichroism, we determine a transition from a polar-only $4mm$ state to a polar and magnetic state below $\sim 100–130\mathrm{K}$. In combination with theory, the magnetic symmetry has been narrowed to be $G$ type $(4^{\prime }∕m^{\prime }m{m}^{\prime })$ or spin glass. An effective piezoelectric coefficient of $d_{33}\sim 3.1\mathrm{pC}∕\mathrm{N}$ was also measured in the polar state at room temperature.

Figure 1

(Color online) SHG of PVO films on NGO (110) substrates. Shows SHG as a function of incoming light angle for a detector fixed at (a) $p$ polarization and (b) $s$ polarization. (c) Shows the variation of SHG signal, $I_p^{2\omega }(\theta =0°)$, as a function of temperature. (d) Shows the dimensionless effective nonlinear coefficient graphed as a function of temperature which points to a discontinuity between 100 and $130\mathrm{K}$.

Figure 2

(Color online) X-ray linear dichroism for PVO films on LAO (001) substrates. (a) X-ray absorption spectra for both $s$- and $p$-polarized x rays at the V and O edges in PVO. (b) Linear dichroism data for the PVO films. Shows distinct differences between the absorption of $s$- and $p$-polarized x rays. (c) Difference between the linear dichroism at a number of given temperatures and the overall average linear dichroism exhibited by PVO.