Observation of ferromagnetism at room temperature in polycrystalline Zn1-x Fe x O solid solutions synthesized by the precursor method

Polycrystalline Zn1 - x Fe (x) O (0 a parts per thousand currency sign x a parts per thousand currency sign 0.075) solid solutions with the wurtzite structure, which belong to the class of diluted magnetic semiconductors, have been synthesized by the precursor method using a mixed formate of the composition Zn1 - x Fe (x) (HCOO)(2) center dot 2H(2)O as a precursor. It has been found that the iron concentration in Zn1 - x Fe (x) O solid solutions, which exhibit ferromagnetic properties with a high degree of magnetization at room temperature, is determined by two factors: (1) the degree of substitution of iron for zinc in the structure of zinc formate Zn(HCOO)(2) center dot 2H(2)O and, therefore, in the structure of zinc oxide ZnO and (2) the conditions of heat treatment of the precursor. It has been shown using samples with x = 0.025 and 0.05 as an example that the magnetization of Zn1 - x Fe (x) O solid solutions regularly increases with an increase in the iron concentration. Based on the results of the X-ray photoelectron spectroscopy analysis of Zn1 - x Fe (x) O powders, it has been suggested that the iron concentration increases in the surface layer of particles, and the oxidation state of iron is 3+.