Publication details
Ferroelectric Self-Poling in GeTe Films and Crystals
| Authors | |
|---|---|
| Year of publication | 2019 |
| Type | Article in Periodical |
| Magazine / Source | CRYSTALS |
| MU Faculty or unit | |
| Citation | |
| Web | https://www.mdpi.com/2073-4352/9/7/335 |
| Doi | http://dx.doi.org/10.3390/cryst9070335 |
| Keywords | self-polarization; ferroelectricity; microstructure; EXAFS; PFM; anomalous diffraction; thin films; single crystals |
| Description | Ferroelectric materials are used in actuators or sensors because of their non-volatile macroscopic electric polarization. GeTe is the simplest known diatomic ferroelectric endowed with exceedingly complex physics related to its crystalline, amorphous, thermoelectric, and-fairly recently discovered-topological properties, making the material potentially interesting for spintronics applications. Typically, ferroelectric materials possess random oriented domains that need poling to achieve macroscopic polarization. By using X-ray absorption fine structure spectroscopy complemented with anomalous diffraction and piezo-response force microscopy, we investigated the bulk ferroelectric structure of GeTe crystals and thin films. Both feature multi-domain structures in the form of oblique domains for films and domain colonies inside crystals. Despite these multi-domain structures which are expected to randomize the polarization direction, our experimental results show that at room temperature there is a preferential ferroelectric order remarkably consistent with theoretical predictions from ideal GeTe crystals. This robust self-poled state has high piezoelectricity and additional poling reveals persistent memory effects. |