Browsing School of Physics by Author "WU, HAN-CHUN"
Now showing items 1-13 of 13
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Anomalous magnetization reversal due to proximity effect of antiphase boundaries
SHVETS, IGOR; WU, HAN-CHUN (2011)Here we report anomalous double switching hysteresis loop and high coercivity (~0.1 T) in Fe3O4(110) thin films. Our analytical model based on spin chains confined within small antiphase boundary domains (APBDs) suggests ... -
Antiferromagnetic interlayer exchange coupling between Fe3O4 layers across a nonmagnetic MgO dielectric layer
SHVETS, IGOR; WU, HAN-CHUN; ARORA, SUNIL (2008)We have investigated the interlayer exchange coupling between the epitaxial spinel Fe3O4 layers across an insulating nonmagnetic MgO spacer. The epitaxial structure used for these investigations was Fe3O4 (10?nm)/MgO ... -
The effect of deposition power on the electrical properties of Al-doped zinc oxide thin films
SHVETS, IGOR; WU, HAN-CHUN (2010)We investigated the effect on the electronic properties of aluminum (Al)-zinc oxide (ZnO) films by modulating the radio frequency sputtering power. Our experimental results show that increasing the sputtering power increases ... -
Giant magnetic moment in epitaxial Fe3O4 thin films on MgO (100)
SHVETS, IGOR; ARORA, SUNIL; WU, HAN-CHUN (2008)Magnetization studies on well characterized epitaxial magnetite (Fe3O4) thin films grown on MgO(100) show that the ultrathin films (<5?nm thickness) are ferromagnetic and their magnetic moments are much greater than those ... -
Inverted magnetoresistance in dual spin valve structures with a synthetic antiferromagnetic free layer
SHVETS, IGOR; COEY, JOHN; FOWLEY, CIARAN; WU, HAN-CHUN (2009)We report an oscillation of the giant magnetoresistance GMR ratio as a function of Ru layer thickness in the CoFe/Cu/ CoFe/Ru/CoFe SAF/Cu/CoFe/IrMn dual spin valve SV structure. A normal GMR with a positive sign is ... -
Large magnetoresistance in few layer graphene stacks with current perpendicular to plane geometry
CROSS, GRAHAM; DUESBERG, GEORG; SHVETS, IGOR; WU, HAN-CHUN (2012)Large magnetoresistance (MR) effect of few layers graphene between two non-magnetic metal electrodes with current perpendicular to graphene plane was studied. A non-saturation and anisotropic MR with the value over 60% at ... -
Magnetic properties of the magnetoelectric compound Cu2OSeO3: Magnetization and 77Se NMR study
WU, HAN-CHUN; SHVETS, IGOR (2011)We present magnetization and 77Se Nuclear Magnetic Resonance (NMR) measurements in single crystals of the magneteoelectric compound Cu2OSeO3. The temperature and field dependence of the magnetization suggest a ferrimagnetic ... -
Magnetic Properties of Ultrathin Magnetite Films Grown by Molecular Beam Epitaxy
SHVETS, IGOR; ARORA, SUNIL; WU, HAN-CHUN (IEEE-INSTITUTE OF ELECTRICAL AND ELECTRONIC ENGINEERS INC, 2008)Magnetic properties as a function of film thickness (2-55 nm) for magnetite (Fe3O4) thin films grown on MgO (100) substrates show that the small thickness films (les 5 nm) are ferromagnetic and possess magnetization values ... -
Rotational transitions in a C60 monolayer on the WO2/W(110) surface
SHVETS, IGOR; KRASNIKOV, SERGEY; LUBBEN, OLAF; MURPHY, BARRY; WU, HAN-CHUN; BULFIN, BRENDAN (2011)Variable-temperature scanning tunneling microscopy (STM) is shown to be an effective technique to study two-dimensional phase transitions. Observations show that a monolayer of C60 deposited on an ultrathin WO2 layer grown ... -
Strain induced exciton fine-structure splitting and shift in bent ZnO microwires
SHVETS, IGOR; WU, HAN-CHUN (2012)Lattice strain is a useful and economic way to tune the device performance and is commonly present in nanostructures. Here, we investigated for the first time the exciton spectra evolution in bent ZnO microwires along ... -
Surface plasmon on topological insulator/dielectric interface enhanced ZnO ultraviolet photoluminescence
SHVETS, IGOR; FLEISCHER, KARSTEN; WU, HAN-CHUN (2012)It has recently been predicted that the surface plasmons are allowed to exist on the interface between a topological insulator and vacuum. Surface plasmons can be employed to enhance the optical emission from various ... -
Temperature dependent coercivity crossover in pseudo-spin-valve magnetic tunnel junctions with perpendicular anisotropy
COEY, JOHN; WU, HAN-CHUN (2011)We report the temperature dependent collapse of tunnel magnetoresistance (TMR) in perpendicular anisotropy magnetic tunnel junctions (pMTJs) with AlO(x) barriers and (Co/Pt)(3) multilayer electrodes, due to the coercivity ... -
Thickness dependence of the effective damping in epitaxial Fe3O4/MgO thin films
WU, HAN-CHUN; SHVETS, IGOR (2011)The precessional magnetization dynamics of high quality epitaxial magnetite (Fe3O4) thin films growth on MgO are investigated by inductive magnetization dynamic measurements in time and frequency domain. An upper bound for ...