A magnetic wire is one of the attractive candidates for high capacity memories and logic devices with low power consumption 1. We reported that the wire of rare-earth transition metal (RE-TM) amorphous alloy show a current induced domain wall motion (CIDWM) with a faster wall speed of more than 1000 m/sec and a current induced magnetization switching (CIMS) with a lower current density of 5.5 MA/cm2 2, 3. However, domain creation method in the wire is one of the key technologies for their applications 4, 5. In this paper, we demonstrate a laser assisted current induced magnetization switching in TbCo/Pt hetero-structure wire.
Figure 1 shows measuring setup for laser assisted current induced magnetization switching. A wire of 3 µm width is irradiated by laser spot of 1 µm diameter under applying both pulse current and external field. The film was fabricated on a thermally oxidized silicon substrate using a sputtering system. TbCo 12 nm layer was co-sputtered by Tb and Co targets and Pt layer was sputtered by Pt target as 2 nm under layer and 4 nm heavy metal layer. The film was patterned by SEM lithography with a liftoff method. CIMS was observed using a MOKE microscope.
Figure 2 shows 100 nsec pulse current dependencies of magnetizing switched domain diameter with/without laser assist, where external in-plane field of 500 Oe. The inset shows microscope view of the wire. Blue line showed a CIMS threshold for without laser assist. CIMS domain diameter increased with increasing current pulse heights. Laser assisted CIMS could reduce the threshold current more than 40 % that of without a laser assisted.
We demonstrated the laser assisted current induced magnetization switching of the magnetic wire. The method can reduce the current and controlled CIMS by laser. The laser assist CIMS is one of the attractive methods to create the domains in the magnetic wire.
This research was supported by KAKENHI (No. 20H02185, 21K18735, 21K14202), Japan.
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