Structural study of Mn-doped ZnO films by TEM

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.…”

X-ray absorption spectroscopy of Mn doped ZnO thin films prepared by rf sputtering technique

“…magnetron sputtering, while thin films prepared by pulsed laser deposition shows paramagnetic 21,22 as well as ferromagnetic 23,24 behaviour at room temperature. Thus a wide variation exists in the results reported by various researchers in the literature and also the origin of ferromagnetism in these DMS thin film systems is still an open question, particularly whether FM arises due to uniformly distributed TM cations in the semiconductor lattice or due to precipitation of metallic clusters in a homogeneous ZnO host matrix 26 or due to the presence of an entirely separate magnetic phase 27 or due to defects 18 is still to be resolved. Thus further experimental and theoretical studies are required in this direction and particularly investigation on the local environment around the host and the dopant cations by X-ray Absorption Fine Structure (XAFS) technique, which include both EXAFS (Extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure), can be very helpful since XAFS gives the local structure information (like bond length, coordination number, disorder, coordination geometry and oxidation state) of the selected element in a system by tuning incident photon energy to its X-ray K edge or L edge energy.…”

Co doped ZnO semiconductor materials: structural, morphological and magnetic properties

“…A large number of experimental studies seem to provide evidence for carrier-mediated RT ferromagnetism in ZnO:TM [15,16]. Recent reports starting from the fact that TM-doped ZnO is known to form nanosized (inter)metallic inclusions [17][18][19][20], consider these inclusions responsible for the observed magnetic response [21].…”