ZnO-based semimagnetic semiconductors: growth and magnetism aspects

Increase of Mn solubility with decreasing grain size in ZnO

“…19 The solubility of Mn in ZnO reaches about 30 at% at 800 • C and falls to 5 at% at 400 • C. This line corresponds to the solubility in the volume of ZnO, the number of Mn atoms segregated in grain boundaries is negligible. 15,16,20,21,[28][29][30][31][32][33][34][35][36][37][38] In Fig. 5 the solubility limit (solvus) of Mn in ZnO polycrystals is drawn using the data on polycrystals with grain size between 100 and 1000 nm.…”

“…6 the solubility limit (solvus) of Mn in ZnO polycrystals is drawn using the data on polycrystals with grain size between 10 and 100 nm. 15,16,20,[28][29][30][31][32][33][34][35][36][37][38] These samples were obtained by the pulsed laser deposition, 15,16,20,21,[28][29][30][31] full or partial sintering of very fine powders, 32-35 partial sintering of nanowires, 36,37 and magnetron sputtering. 38 The solubility of Mn in ZnO drastically increased in comparison with Fig.…”

Magnetization study of nanograined pure and Mn-doped ZnO films: Formation of a ferromagnetic grain-boundary foam

“…3-6͒ exhibit FM in many cases, while ZnO synthesized by wet chemistry methods or chemical vapor deposition ͑CVD͒ has intermediate properties; it can be either paramagnetic or FM. 2,[33][34][35][36][37][38][39][40][41][42] In order to quantify the defects and grain boundaries ͑GB͒ we introduced the specific GB area, s GB , the ratio of grainboundary area to volume, and determined it from published works devoted to the search of FM in pure and Mn-doped ZnO. In the case of single crystals 25,32,38 or doped ZnO films deposited on the ZnO single crystal, 54 no GBs are present, and since formally the s GB value is very large for them, the value s GB =4ϫ 10 2 m 2 / m 3 was chosen to indicate data for such single crystals close to the left margin in Fig.…”

Photoacoustic Spectra and Thermoelectric Properties of Amorphous Si/Au/Ge/Au Superlattice

“…Another reason might relate to the high content of manganese. Mn ions are antiferromagnetically coupled via the exchange interactions; thus the magnetization will be reduced with increasing manganese [14].…”