(Invited) Electrodeposition of Manganese Arsenides (MnxAs) as Promising Candidates in Spintronics
Authors: Giurlani Walter , Pappaianni Giulio , Bonechi Marco , Calisi Nicola , Mannini Matteo , Bazzicalupi Carla , Fontanesi Claudio , Innocenti Massimo 
Published: September 2023

Spintronics is a new branch of electronics in which the spin of the electrons as well as their charge is manipulated to produce a desired outcome. Spintronic devices are particularly attractive for memory storage and magnetic sensor applications, and potentially for quantum computing where the electron spin would represent a bit of information. Nowadays many efforts are made to increase the efficiency and lower the production costs of these materials, among others the use of molecular inorganic compounds and cheap preparation techniques [1].

Most of these layers are synthesized with physical and/or vapor phase techniques [2] which allow to obtain materials with a very few defects, but which are complex to manage and typically very expensive. For this reason, in this study we have searched for a way to electrochemically deposit a compound with interesting spintronic properties in the aqueous medium. In fact, electrodeposition is notoriously a very cheap, versatile and easily scalable technique.

With this purpose Mn-As system was selected thanks to its good magnetic and transport properties to be used as building blocks for spin valve [3]. MnAs has potential applications in spintronics, for electrical spin injection into GaAs and Si based devices [4] and DFT simulations predict that Mn2As and Mn3As have a low magnetization saturation and a high spin polarization at the Fermi-level [5]. Starting from MnSO4 and NaAsO2 precursors solutions with various concentrations, supporting electrolytes and pH were tested.

The electrochemical behaviour of the precursors was investigated with cyclic voltammetries and both potentiostatic as well as galvanostatic deposition were carried out. The deposits obtained were morphologically and compositional characterised with scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray fluorescence spectroscopy (XRF), the chemical states were analysed with X-ray photoelectron spectroscopy (XPS), the crystalline structure was investigated with X-ray diffraction measurements (XRD). The preliminary magnetic and transport measurements evidence the promising properties of this deposition process to provide spinfiltering materials.

The authors acknowledge Regione Toscana POR CreO FESR 2014-2020 – azione 1.1.5 sub-azione A1 – Bando 1 “Progetti Strategici di ricerca e sviluppo” which made possible the project “RAM-PVD” (CUP 3647.04032020.157000057_1225).

References

[1] M. Innocenti et al., Journal of Electroanalytical Chemistry 2020, 856, 113705, doi: 10.1016/j.jelechem.2019.113705

[2] M. Yuzuri et al., JJournal of the Physical Society of Japan, 1960, 15, 1845-1850, doi: 10.1143/JPSJ.15.1845

[3] T. Graf et al., Progress in Solid State Chemistry 2011, 39, 1-50, doi: 10.1016/j.progsolidstchem.2011.02.001

[4] C. Mocuta et al. Scientific Reports 2017, 7, 16970, doi: 10.1038/s41598-017-17251-y

[5] Heusler database: http://heusleralloys.mint.ua.edu/