Abstract
This article reports results of the investigation of the effect of the external magnetic field variation on the spin wave interference in a magnetic cross junction. The experiments were performed using a micrometer scale Y3Fe5O12 cross structure with a set of micro-antennas fabricated on the edges of the cross arms. Two of the antennas were used for the spin wave excitation while a third antenna was used for detecting the inductive voltage produced by the interfering spin waves. It was found that a small variation of the bias magnetic field may result in a significant change of the output inductive voltage. The effect is most prominent under the destructive interference condition. The maximum response exceeds 30 dB per 0.1 Oe at room temperature. It takes a relatively small bias magnetic field variation of about 1 Oe to drive the system from the destructive to the constructive interference conditions. The switching is accompanied by a significant, up to 50 dB, change in the output voltage. The obtained results demonstrate a feasibility of the efficient spin wave interference control by an external magnetic field, which may be utilized for engineering novel type of magnetometers and magnonic logic devices.
Highlights
Magnonics is a new rapidly developing field of science and engineering, focused on studying collective spin excitations, i.e. spin waves, and devices, which utilize such excitations for their operation.[1]
In our prior works,[8,9] we studied the spin wave interference in the magnetic cross junctions
We study the effect of the magnetic field variation on the spin wave interference in a magnetic cross junction
Summary
A cross junction is made of a single crystal YIG film epitaxially grown on top of a Gadolinium Gallium Garnett (Gd3Ga5O12) substrate using the liquid-phase transition process. The saturation magnetization of the structure is 4πM0 ≈ 1750 G, and Ferromagnetic resonance (FMR) linewidth is ∆H ≈ 0.5 Oe. There are four Π-shaped micro-antennas fabricated on the edges of the cross. Two of the antennas (numbered 1 and 2 in Fig.1) are used to generate the input waves. The spin waves are excited by a magnetic field generated by the AC electric current flowing through the antennas. Antennas 3 and 4 are used to detect the inductive voltage produced by the spin wave interference. Details of the inductive measurement technique can be found elsewhere.[11] The phase between the input spin waves is controlled by the phase shifters (ARRA 9428A).
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