# Magnetic Field Effect on the Handedness of Electrodeposited Heusler Alloy
## 2 Materials and Methods  
We chose to investigate Co\({}_{2}\)FeSn Heusler alloy that was prepared galvanostatically. To prepare the sample, the composition of the solution was based on the work of [PERSON] et al. [15] which consisted of: CoSO\({}_{4}\) 75 mM; FeSO\({}_{4}\) 50 mM; SnSO\({}_{4}\) 8.3 mM; sodium D(+)-gluconate 120 g/L; tryptone (peptone from casein) 0.1 g/L; L(+)-ascorbic acid stabilizer 2 g/L; NaCl 0.3 M; and boric acid 0.3 M. Besides the metal precursors, gluconate is used as a complex agent toward tin; ascorbic acid as a stabilizing agent; peptone as a brightener; NaCl as the supporting electrolyte; and boric acid as the buffer. We have found that the sequence of solution preparation is important in bringing all the components into the solution. Initially, the ascorbic acid solution was prepared with sodium gluconate, then the metals' salts were added one by one starting with tin sulphate and waiting until the complete dissolution before proceeding with the next salt. The dissolution was facilitated by using an ultrasonic bath. Then, tryptone, NaCl, and boric acid were added in this order. Finally, the pH of the solution was raised to 7 using NaOH. The fresh solution has a burgundy colour but tends to age quickly producing a brown colour. The solution was kept at 60 \({}^{\circ}\)C during the measurements and depositions.  
The electrochemical measurements were conducted with a three-electrode setup: the working electrode (WE) was a commercial (100) silicon wafer at 1 mm thick and coated with \(\approx\) 100 nm of gold. The adhesion layer between Si and Au was made of \(\approx\)5 nm of Ti to avoid interferences during the magnetic measurements. The electrode was flame annealed before the measurements and depositions to rearrange the crystalline structure of gold from monocrystalline to (111) [33]. Ag/AgCl sat. KCl was used as a reference electrode (RE) and a platinum mesh as a counter electrode (CE).  
The electrochemical cell (Figure 1) is a cylinder with a diameter of 2.2 cm and a height of 2.2 cm. On the bottom of the cell is a hole of 8.5 mm in diameter where the WE is in contact with the solution. The total amount of solution in the cell was \(\approx\)8 mL. There is a plastic support under the WE to house the magnet.  
Figure 1: Schematic view of the experimental setup.  
A D66-N52 magnet (K&J magnetics, Inc., Pipersville, PA, USA) was used for the measurements by placing it below the electrochemical cell. The magnet is 3/8'' in diameter and 3/8'' thick, NdFeB Grade N52, with a surface field of 6619 Gauss. This value is high enough ensuring to work in a magnetic field that is higher than the saturation magnetization of the electrodeposited compound (980 emu/cm\({}^{3}\)) [34].  
Scanning electron microscopy (SEM-EDS) images and microanalysis were acquired using a Hitachi SU3800 that was equipped with an Ultim Max 40 Analytical Silicon Drift EDS Detector using an accelerating voltage of 10 kV.  
XRF spectra were acquired with a Bowman BA-100 using 50 kV tube voltage, a 0.8 mA current tube, a 0.6 mm collimator diameter, and a 0.5 mm Al filter in air.  
Spectra were collected using the larger collimator (10 mm) to achieve better counting statistics since no restrictions were related to sample geometry; the acquisition time was set to 60 s as a trade-off between accuracy and duration of the measurement session. Powder X-ray Diffraction (PXRD) patterns were recorded on a Bruker New D8 Advance DAVINCI diffractometer using Cu K\(\alpha\) radiation (\(\lambda\) = 1.540 A), a 0.6 mm Ni collimator and 0.02 mm Ni filter, a fast multichannel energy-discriminator detector, and a flat holder. Patterns were obtained by using a Bragg-Brentano configuration in the \(\theta\)/20 30\({}^{\circ}\)-90\({}^{\circ}\) range.  
Field-dependent direct current (DC) magnetic measurements were conducted on a Quantum Design MPMS SQUID magnetometer at 5 K, with the field oriented parallel to the plane of the sample.