Ultrathin chromia films grown with preferential texture on metallic, semimetallic and insulating substrates

Spin polarization asymmetry at the surface of chromia

“…The observation of two types of step heights and local conductivities suggests that two characteristic surface terminations corresponding to different cuts through the [18] suggest that the surface of Cr 2 O 3 is Cr-terminated and thermodynamically stable in a broad temperature range between 165 K and well above room temperature, although detailed models invoking fractional Cr-layer occupancy have also been discussed [17,19]. The predicted stability of Cr termination [18] clearly speaks against the coexistence of Cr-and O-terminated surfaces, consistent with experimental results [13,20,21]. Moreover, our frequent experimental observation of conductivity domains that do not correlate with steps in the film, such as those in figures 3(c), (d), as well as the highlighted region in figure 3(b), are also inconsistent with the assumption of variations in the surface termination.…”

“…The Cu(111) single crystal of purity >99.999% was prepared by repeated cycles of Ar ion sputtering and annealing at a temperature of 850 K. The chromia thin film on the Cu (111) substrate was prepared by evaporation of two monolayers of metallic chromium onto the clean Cu(111) surface from an e-beam heated crucible evaporator, followed by annealing to 920 K for 1 min in a partial oxygen pressure at 5 × 10 −7 Torr. As described elsewhere [13,14], this leads to a very flat chromia thin film with pronounced texture along (0001) and little or no mosaic spread. Samples were imaged with a low-temperature scanning tunneling microscope (Omicron Nanotechnology).…”

“…Variations in surface magnetization with chromia film thickness STM images of very thin chromium oxide Cr 2 O 3 (0001) films on Cu(111) are shown in figure 3. The island sizes are quite large [13], typically several micrometers, and the islands usually extend over several substrate terraces. The Cu substrate is also visible between the islands.…”

Crystal Structure Manipulation of the Exchange Bias in an Antiferromagnetic Film

“…The crystal orientation of Cr 2 O 3 films has been shown to be highly associated to the substrate crystalline structures. For example, preferential oriented growth of Cr 2 O 3 is achieved on oriented Al 2 O 3 , Co, and oriented Cu and oriented Cr 2 O 3 is grown on Fe films 15 19 20 . The growth mode of Cr 2 O 3 film in our study is similar to that observed in an earlier report for the oriented Fe 2 O 3 films grown on rutile .TiO 2 substrates 21 .…”

Magnetoelectric oxide films for spin manipulation in graphene

“…Remarkably, high‐quality crystalline EuO growth on top graphene has been demonstrated using oxide molecular beam epitaxy even though lattice and symmetry matching at the interface is not ideal . Along with other reports of Cr 2 O 3 growth on graphitic carbon , this indicates a very promising future for functional oxide film growth on graphene.…”