**2.3. Synthesis of magnetic iron compounds**

For the synthesis of magnetic nano– and micro–iron oxide particles, the solid iron targets were ablated immersed in an aqueous solution of basic pH. As a result of the iron ablation, we observed the formation of ions ferrate (VI), α-iron and the unusual form of iron oxides FeO. The aim of this study is to evaluate how the material contained in the plasma plume formed by the laser ablation of an iron target evolves into a medium of high pH and chemically reacts with the solution to form iron oxides. We also examined how the fluency of laser pulses applied to solid iron target surface influences the preparation process.

For this experiment, we used Fe plates that were chemically cleaned, washed with water and then subjected to ultrasonic bath in ethanol for 5 min. The ambient liquid used was a solution with a concentration of 1 molar sodium hydroxide in distilled water and measurements indicated that the pH of the solution was 14. The ALAL was performed with three laser beam fluency values, the materials prepared under these conditions were designated as Type1, Type2 and Type3 and **Table 1** shows the synthesis parameters used for the preparation of these samples. All experiments were conducted at a temperature of 293 K and pressure of 1 atm. To minimize the number of variables in the preparation process, the same values for repetition rate of the laser pulses and the height of the liquid layer on the solid target (10 mm) were used, both for the volume to the liquid environment and for the laser ablation time at which the target has been subjected.


**Table 1.** Experimental parameters for ALAL of iron plates.
