View Record

TitleStructure and spin dynamics in Cr Doped ZnO
AuthorAmami, Paul Erhire
SubjectSemiconductors
SubjectMagnetic properties
SubjectRaman spectroscopy
SubjectX-ray diffraction
SubjectElectronic paramagnetic resonance
SubjectPhotoluminescence spectroscopy
SubjectFerromagnetism
SubjectDiluted magnetic semiconductors
SubjectAnti-ferromagnetism
SubjectParamagnetism
Subject537.6223
SubjectSemiconductors
SubjectRaman spectroscopy
SubjectFerromagnetism
SubjectDiluted magnetic semiconductors
SubjectParamagnetism
Date2017-07-14T05:55:49Z
Date2017-07-14T05:55:49Z
Date2016-06
TypeDissertation
Format1 online resource (xii, 91 leaves) : illustrations (some color)
AbstractPolycrystalline Zn1-xCrxO (0.01 ≤ x ≤ 0.09) samples synthesized by solid state reaction technique were sintered at different temperatures following slow step sintering schedule. Structural, micro-structural, optical, magnetic properties and homogeneity were investigated using suitable characterisation techniques. Cr2O3 and CrO2 phases have been detected in the XRD patterns and Raman spectra of Zn1-xCrxO samples with x ≥ 0.05. Photoluminescence study has indicated improved optical property of the samples compared to undoped ZnO. While low percentage Cr doped samples showed diamagnetic behaviour, higher percentage doped samples (≥ 5%) exhibited ferromagnetic, paramagnetic and anti-ferromagnetic behaviours depending upon the sintering temperatures. The magnetic properties have been analysed through Electron Spin Resonance study. A g-value of 1.97 indicates Cr in +3 valence state in doped ZnO system. Presence of Cr3+ and Cr4+ in ZnO is understood to facilitate super exchange interactions to promote ferromagnetism at room temperature. ESR study shows improved magnetic homogeneity achieved by slow step sintering process.
AbstractPhysics
AbstractM. Sc. (Physics)
IdentifierAmami, Paul Erhire (2016) Structure and spin dynamics in Cr Doped ZnO, University of South Africa, Pretoria,
Identifierhttp://hdl.handle.net/10500/22833