Spin wave interference in YIG cross junction

M Balinskiy,Y Filimonov,A Khitun,A Kozhevnikov,H Chiang,D Gutierrez

doi:10.1063/1.4974526

Abstract

This work is aimed at studying the interference between backward volume magnetostatic spin waves and magnetostatic surface spin waves in a magnetic cross junction. These two types of magnetostatic waves possess different dispersion with zero frequency overlap in infinite magnetic films. However, the interference may be observed in finite structures due to the effect magnetic shape anisotropy. We report experimental data on spin wave interference in a micrometer size Y3Fe2(FeO4)3 cross junction. There are four micro antennas fabricated at the edges of the cross arms. Two of these antennas located on the orthogonal arms are used for spin wave generation, and the other two antennas are used for the inductive voltage detection. The phase difference between the input signals is controlled by the phase shifter. Prominent spin wave interference is observed at the selected combination of operational frequency and bias magnetic field. The maximum On/Off ratio exceeds 30dB at room temperature. The obtained results are important for a variety of magnetic devices based on spin wave interference.

Highlights

Spin wave is a collective excitation of the electron spin system in ferromagnetic metals or insulators.[1]
The black curve shows the inductive voltage in case the bias magnetic field H = 798 Oe is directed along the virtual line connecting ports 1 and 3
The minimum output voltage is observed in the case of destructive spin wave interference modulation, when two spin waves are coming with a π-phase difference

Summary

INTRODUCTION

Spin wave is a collective excitation of the electron spin system in ferromagnetic metals or insulators.[1] The collective nature of spin waves manifests itself in a relatively long coherence length, which may exceed hundreds of micrometers in conducting materials (e.g. NiFe2) and even centimeters in non-conducting ferrites (e.g. YIG3) at room temperature The later makes it possible to exploit spin wave interference in a variety of micro- and nano-scale devices.[4,5,6] Potentially, spin wave devices may provide a route towards scalable devices convenient for in-chip integration.[7] One of the main challenges is associated with the spin wave interconnects including orthogonal (e.g. cross shape) junctions.

PHYSICAL MODEL

MATERIAL STRUCTURE AND EXPERIMENTAL DATA

DISCUSSION

CONCLUSIONS