The Fe/ZnO(0001) interface: Formation and thermal stability

Epitaxial growth of ZnO films on thin FeO(111) layers

“…For Fe, the most intense Fe 2p core level is split into 2p 3/2 and 2p 1/2 due to the spin-orbit coupling. It is known that the BEs of Fe 2p 3/2 core levels in Fe, FeO, Fe 3 O 4 and Fe 2 O 3 are 707.0, 710.0, 710.6 and 711.0 eV, respectively [11][12][13][14]. In addition, for Fe 2+ or Fe 3+ 2p core level, observable satellite peaks with different BE position originating from shake-up processes can also be used to characterize their chemical states [10,13].…”

“…The value of BE is 1021.5 eV for Zn 2p 3/2 core level, corresponding to either ZnO or metallic Zn [16]. In XPS measurements, it is difficult to distinguish various chemical states of Zn-based materials by measuring 2p 3/2 line alone due to close BE values between Zn 2+ and Zn 0 states [14]. However, the corresponding Auger parameter (a ¼ BE (Zn 2p 3/2 )+ KE (Zn LMM), KE = kinetic energy) value is 2010.6 eV, which strongly suggests the existence of Zn 2+ , i.e.…”

Magnetism modulation of Fe/ZnO heterostructure by interface oxidation

“…7 Results of Wett et al show that, at ambient temperature, Fe grows on ZnO(0001) in the pseudo layer-by-layer mode with the FeO formation at the interface. 8 Annealing leads to a stepwise oxidation of the Fe to FeO (670 K) and Fe 2 O 3 (820 K). 8 However, the corresponding evolution of the magnetic behavior is still lacking.…”

“…8 Annealing leads to a stepwise oxidation of the Fe to FeO (670 K) and Fe 2 O 3 (820 K). 8 However, the corresponding evolution of the magnetic behavior is still lacking. Study of Zhou et al finds enhanced coercivity in the FePt/ZnO core/ shell nanoparticles after annealing at 773 K, but without further chemical state analysis.…”

Voltage-induced reversible changes in the magnetic coercivity of Fe/ZnO heterostructures

“…In the study of Wett et al on the Fe/ZnO(0001) system at ambient temperature, FeO was formed at the interface. 25 Further annealing led to a stepwise oxidation of Fe to FeO (670 K) and Fe 2 O 3 (820 K). Their experiment was mostly performed on 2.4 nm Fe/ZnO(0001) and the XPS measurement monitored the surface top layers.…”