Current-controlled magnon propagation in Pt/Y3Fe5O12 heterostructure

Abstract

We present a dynamic spin wave (SW) modulation technique using direct current (DC) to manipulate the magnetic properties of an ultralow-damping Y3Fe5O12 thin film. The microwave excitation and detection technique with two coplanar waveguide antenna arrangements on the Y3Fe5O12 (YIG) surface is used to characterize the SW. An additional platinum (Pt) stripe connected to a current source is integrated between the coplanar waveguide pair to demonstrate the SW resonant frequency and amplitude modulation by current induction. We selected a Pt stripe due to its significantly lower spin wave absorption property. The application of current through the Pt stripe generates local joule heating that modifies the magnetic properties of the YIG film. Temperature variation through local heating modifies the saturation magnetization of the YIG film, which, in turn, modulates the SW frequency. Moreover, the amplitude of the SW spectra is found to be tuned by the current amplitude. This phenomenon is mainly described by magnon–magnon scattering induced by the spin Seebeck effect in the case of local heating. Furthermore, the group velocity of the proposed device is also found to be responsive to the current, which has been explained by both magnon–magnon and magnon-phonon scattering.