Exploring the magnetic ground state of vanadium doped zinc sulphide

Abstract

Vanadium doped ZnS quantum dots (QDs) were synthesized with the generic formula Zn 1-x V x S (where x=0, 0.05, 0.10 and 0.15). Polyvinylpyrrolidone capped QDs were prepared by chemical co-precipitation technique. The phase purity of the samples were confirmed by x-ray diffraction. Crystallite size of 1.7-2.2 nm was obtained from the Scherrer's formula. Optical absorption studies revealed a band gap varying from 3.9 to 4.1 eV. Photoluminescence studies revealed a strong blue shift due to the strong quantum confinement in the particles. Magnetic studies indicated a ferromagnetic ground state for the doped samples.

Cobalt-substituted ZnS QDs: a diluted magnetic semiconductor and efficient photocatalyst

“…The lattice constant ( a ) of the unit cell for all the Co x Zn 1− x S QDs was obtained using the following relation: 13,24,25 where hkl denotes the Miller indices and others are known symbols. The estimated values of lattice constant for all the QD samples are presented in Table 1.…”

“…13 The calculated values of mean crystallite size as seen from Table 1 for all the doped and undoped samples were found well below the Bohr excitonic radius, causing strong quantum connement effects. 13 The lattice constant (a) of the unit cell for all the Co x Zn 1−x S QDs was obtained using the following relation: 13,24,25…”

Introducing the magnetic properties in Fe doped ZnO nanoparticles for spintronics application

“…Fe doped ZnO nanoparticles with a generic formula Zn 1-x Fe x O (x = 0.00, 0.05, 0.10 and 0.15) were fabricated using standard chemical co-precipitation method [4,22]. Raw chemicals ZnCl 2 and FeCl 2 were used for synthesizing nanoparticles.…”

“…Therefore, magnetic interactions are mediated by the hopping of electrons between Fe ions having oxidation states differ by one unit. This mechanism leads to ferromagnetic coupling of Fe ions in the host ZnO matrix[22,35]. For this reason, the entire Fe ions doped ZnO samples showed weak ferromagnetism at room temperature.…”

“…Generally n-type ZnO nanoparticles are readily available and several intrinsic defects (Znvacancies) also lead to arrival of high T C ferromagnetism. Slow incorporation of magnetic cations (Fe ions) in nanosized ZnO favored the sp-d or p-d hybridization and also resulted in weak ferromagnetism at 300 K[10,22]. The nanosized ZnO sample doped with 15% Fe ions showed highest value of coercive field (101 Oe).…”