Switchable giant nonreciprocal frequency shift of propagating spin waves in synthetic antiferromagnets

• Published in: Science advances Vol. 6; no. 17; p. eaaz6931
• Main Authors: Ishibashi, Mio, Shiota, Yoichi, Li, Tian, Funada, Shinsaku, Moriyama, Takahiro, Ono, Teruo
• Format: Journal Article
• Language: English
• Published: American Association for the Advancement of Science 01.04.2020
• Subjects: Applied Physics; Condensed Matter Physics; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aaz6931

We report the giant nonreciprocity and the electrical switching of propagating spin waves in synthetic antiferromagnets. The nonreciprocity of propagating spin waves, i.e., the difference in amplitude and/or frequency depending on the propagation direction, is essential for the realization of spin wave–based logic circuits. However, the nonreciprocal frequency shifts demonstrated so far are not large enough for applications because they originate from interfacial effects. In addition, switching of the spin wave nonreciprocity in the electrical way remains a challenging issue. Here, we show a switchable giant nonreciprocal frequency shift of propagating spin waves in interlayer exchange–coupled synthetic antiferromagnets. The observed frequency shift is attributed to large asymmetric spin wave dispersion caused by a mutual dipolar interaction between two magnetic layers. Furthermore, we find that the sign of the frequency shift depends on relative configuration of two magnetizations, based on which we demonstrate an electrical switching of the nonreciprocity. Our findings provide a route for switchable and highly nonreciprocal spin wave–based applications.