[18a-D704-1~11] 10.2 スピン基盤技術・萌芽的デバイス技術

▼ [18a-D704-9] Emergence of large spin-charge interconversion at an oxidized Cu/W interface

〇(P)Inge Groen^1,2、Van Tuong Pham³、Stefan Ilic⁴、Won Young Choi¹、Andrey Chuvilin^1,6、Edurne Sagasta¹、Diogo C. Vaz¹、Isabel C. Arango¹、Nerea Ontoso¹、F. Sebastian Bergeret^4,5、Luis E. Hueso^1,6、Ilya V. Tokatly^5,6,7、Felix Casanova^1,6 (1.CIC nanoGUNE BRTA、2.Kyoto Univ.、3.Univ. Grenoble Alpes, CNRS, Institut Neel、4.CFM-MPC、5.DIPC、6.IKERBASQUE、7.ETSF, Basque Univ.)

キーワード：Spin-charge interconversion, Nanostructure, Lateral spin valve

Spin-orbitronic devices open the possibility to integrate memory and logic by exploiting spin-charge interconversion (SCI). Interfaces are crucial elements in these devices as they can diminish or promote spin flow as well as possess spin-orbit coupling giving rise to interfacial SCI. We study the origin of SCI in a Py/Cu/W lateral spin valve (see fig. 1a) and quantify its efficiency. An exhaustive characterization of the interface between Cu and W electrodes uncovers the presence of an oxidized layer WO_x (see fig. 1b). Figure 1c shows the SCI observed in this system via the measurement scheme in fig. 1a. After analyses of different spin transport scenarios, we identified that spin absorption and SCI occur at the Cu/oxide interface. We find a temperature-independent interfacial spin-loss conductance is about 20x10^13 Ohm^-1 m^-2 and a spin-charge conductivity = -1610 Ohm^-1 cm^-1 at 10 K (-830 Ohm^-1 cm^-1 at 300 K). This corresponds to an efficiency length for the Cu/oxide interface given by inverse Edelstein effect ranging from -0.76 nm to -0.4 nm for temperatures between 10 K to 300 K, which is notably larger than other metallic interfaces [1,2] or even Pt [3]. The large SCI efficiency at this oxidized interface is promising for development of magnetic-state readout in the magnetoelectric spin-orbit (MESO) logic device [4,5]. Moreover, this work highlights the importance of studying every aspect of all-metallic devices carefully, in particular the interface, to extract meaningful spin relaxation and SCI efficiency parameters.