Drivinv

Drivinv

Kết quả (Việt) 2:

Electric-field control of antiferromagnetic textures. Beyond the observations on pristine configurations of ferroelectric domains in which the cycloid propagation is locked onto the polarisation, we now manipulate the ferroelectric order using electric fields, with the aim to design antiferromagnetic landscapes on demand. We first use PFM to draw micron-size ferroelectric domains (Sup- plementary Fig. 7) by virtue of the so-called trailing field24–26. Using microdiffraction experiments, we checked that no strain difference could be detected between artificially written and as- grown striped-domains (Methods and Supplementary Fig. 8). NV magnetometry is then performed on these artificial domains to reveal the corresponding magnetic textures (Fig. 5 and Supple- mentary Fig. 7). For strain states ranging from −0.35 to +0.50%, single ferroelectric domains always correspond to a spin cycloid with a single propagation vector. For BiFeO3 films grown on DyScO3 (−0.35%, Fig. 5a) or TbScO3 (−0.10%, Fig. 5b), the spin cycloid propagates in a direction perpendicular to the ferroelectric polarisation. This implies that the in-plane k1 propagation is still favoured, switching from two pristine cycloid Is to a single written cycloid I. Interestingly, the spin cycloid period λ decreases from about 78 ± 5 nm in the pristine (two domain) state to 65 ± 2 nm for the switched (single domain) state. In single domains, the spin cycloid period thus appears closer to that observed in bulk BiFeO3 (λbulk = 64 nm, ref. 19), suggesting that periodic electric/elastic boundary conditions influence the cycloid period.
For BiFeO3 films grown on GdScO3 (+0.05%, Fig. 5c), the spin cycloid propagates horizontally, i.e. at 45 degrees from the in- plane polarisation variant of the single ferroelectric domain. This implies that the cycloid I out-of-plane propagation vector (k2, Fig. 3a, b) is selected, corresponding to a switching from two cycloid IIs (k1′, k2′) to a single cycloid I (k2). In addition, the apparent cycloid period of 92 ± 3 nm in the single domain is compatible with its projection onto the sample surface

Kết quả (Việt) 3:

德里维诺夫