| In this dissertation,3d-transition-metals-doped ZnTe-based and PbPdO2-based magnetic semiconductors were prepared by a hydrothermal method and a sol-gel spin-coating method, respectively. The samples’magnetic properties were characterized and discussed in detail. The main works and achievements are summarized as follows:(1) ZnTe with low Mn-doping level of about 3 at.% diluted magnetic semiconductor was synthesized by the hydrothermal method. The annealed Zn1-xMnxTe (x=3 at.%) was proved to be the single phase with a zinc blende structure. From the XAS results, Mn ions were determined to occupy the Zn sites and exhibit the valence state of +2. Within the annealed Zn1-xMnxTe (x=3 at.%), it was found that the paramagnetism, superparamagnetism and room-temperature ferromagnetism coexisted and the Te vacancies formed the bound magnetic polaron (BMP) with the neighboring Mn ions. The ferromagnetic coupling between the BMPs was believed to be the origin of the sample’s ferromagnetism.(2) Zn1-xMnxTe (x=3 at.%,6 at.%,13 at.%,18 at.%) with different Mn-doping levels were synthesized by the hydrothermal method. The sample with Mn-doping level of 3 at.% was single phase, while there was MnO impurity phase existing in the samples with Mn doing levels of 6 at.%,13 at.% and 18 at.%. The doped Mn ions was found to have the valence state of +2 in all samples and bond with O ions in Zn1-xMnxTe (x=6 at.%,13 at.%,18 at.%). All samples exhibited the paramagnetic and ferromagnetic signals. Weak antiferromagnetism was also found in the samples with Mn-doing level of 3 at.% and 6 at.%. With the increase of the Mn-doping level, the number of ferromagnetic couplings, especially the weak ones, also increased. The strong ferromagnetic couplings were believed to be the origin of the room-temperature ferromagnetism properties of Zn1-xMnxTe samples.(3) Co-doped PbPdO2 nanograin films with different amount of Pb vacancies were fabricated through controlling the annealing temperature. The increase of the amount of Pb vacancies resulted in the valence state of some Co ions increasing from +2 to +3. Consequently, the spin moments introduced by Co ions, especially Co3+, would increase and enhance the films’ ferromagnetic characteristics. On the other hand, the holes coming from Pb vacancies could promote the antiferromagnetic couplings between Co ions through carrier-mediated mechanism. As the result, antiferromagnetic signal was found in the films annealed at 650℃ and 700℃.(4) Co-doped PbPdO2 nanograin films with the average particle sizes of 30nm,80 nm and 120 nm were obtained by elongating the calcination time from 0.5h to 2.5 h. The Co ions were found to have a mixed valence state of +2 and +3 within all films due to the existence of Pb vacancies. Ferromagnetism, antiferromagnetism, paramagnetism and CO state were found in the Co-doped PbPdO2 films with different particle sizes. It should be noted that the CO state which usually favors the antiferromagnetic configuration showed the relationships with the particle size. With decreasing the particle size from 120 nm to 30 nm, the CO state weakened gradually.(5) Both Mn-doped and (Co,Mn)-codoped PbPdO2 films were comprised of nanograins with average particle size of 30 nm, and had a thickness of about 120 nm. The valence state of Mn ions was between +3 and +4, and the Co ions had the mixed valence of +2 and +3. Compared with the Mn-doped PbPdO2 sample, the introduce of Co ions, especially the Co3+, into the (Co,Mn)-codoped PbPdO2 film could introduce more spin moments. Thus, the enhancement of the ferromagnetic properties was achieved in (Co,Mn)-codoped PbPdO2 film.
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