Woo Seok Choi1
Sungkyunkwan University1
Artificial oxide crystals synthesized by atomic-scale precision epitaxy serves as a prototypical platform for realizing, controlling, and understanding the intriguing coupling between different degrees of freedom with similar energy scale. The excellent tunability of the crystal itself enables observation of exotic functional phenomena, that are not attainable in natural crystals.<br/>In this presentation, we demonstrate an unexpected spiral spin state in synthetic SrRuO<sub>3</sub> heterostructure. The spin state of each SrRuO<sub>3</sub> layer (with a few atomic unit cell thicknesses) within the SrRuO<sub>3</sub>/SrTiO<sub>3</sub> superlattices were characterized using polarized neutron reflectivity (PNR). Exploiting the superlattice structure with the help of magnetization measurements, we proved that the in-plane spin rotates in the SrRuO<sub>3</sub> layers as a function of the SrTiO<sub>3</sub> layer thickness. Based on the spiral spin structure realized in a ferromagnetic metal/nonmagnetic insulator/ferromagnetic metal heterostructure, a novel exchange interaction was proposed, based on chiral symmetry breaking of phonons within the SrRuO<sub>3</sub> layer. The strong chiral phonon-spin coupling observed in the SrRuO<sub>3</sub> heterostructures envisions novel magnetic device utilizing the functional oxide interfaces.<br/> <br/>Jeong <i>et al</i>., <i>Appl. Phys. Lett. </i><b>115</b>, 092905 (2019).<br/>Jeong <i>et al</i>., <i>Phys. Rev. Lett. </i><b>124</b>, 026401 (2020).<br/>Jeong <i>et al</i>., <i>Nanoscale. </i><b>12</b>, 13926 (2020).<br/>Jeong <i>et al</i>., <i>Adv. Sci. </i><b>7</b>, 2001643 (2020).<br/>Seo <i>et al</i>., <i>Phys. Rev. B </i><b>103</b>, 045104 (2021).<br/>Jeong <i>et al</i>., <i>ACS Appl. Nano Mater. </i><b>4</b>, 2160 (2021).<br/>Cho <i>et al.</i>, <i>Acta Mater.</i> <b>216</b>, 117153 (2021).<br/>Jeong <i>et al</i>., submitted (2021).