Self-organized nano-structuring of CoO islands on Fe(001)

Magnetic anisotropy at the buried CoO/Fe interface

“…10,19,23 This result has been accomplished by exploiting an ultra-thin Co buffer layer with a bct cubic structure. 21,24 In that case, the CoO films were also a) Currently at Institute of Applied Physics, TU Wien, Vienna, Austria b) Electronic mail: alberto.brambilla@polimi.it characterized by a well-ordered mesa mound morphology for CoO thicknesses above a few monolayers (ML), occurring on account of stress relaxation through the formation of a network of misfit dislocations. 25,26 In this Letter, we explore the magnetic properties of such an interface and we report on the occurrence of a uniaxial magnetic anisotropy that gives rise to multijump magnetic hysteresis loops.…”

“…17 In particular, the CoO/Fe(001) interface has been a workbench for many investigations related to AF/FM systems with reactive interfaces, ranging from the exchange bias mechanism, 14,18 to the influence of structure and stoichiometry on the magnetic properties, 19 to the realization of peculiar magnetic configurations, like vortices. 20 Very recently, we have demonstrated that it is possible to prepare a CoO/Fe(001) interface characterized by the absence of any Fe oxide, 21,22 which is a quite unique feature with respect to the common experimental situations. 10,19,23 This result has been accomplished by exploiting an ultra-thin Co buffer layer with a bct cubic structure.…”

“…21. Subsequent annealing at 470 K for 5 minutes produces the Co(001)-p(1 × 1)O surface, 24 characterized by a single atomic layer of chemisorbed oxygen, while iron at the interface remains free of oxygen.…”

“…Subsequent annealing at 470 K for 5 minutes produces the Co(001)-p(1 × 1)O surface, 24 characterized by a single atomic layer of chemisorbed oxygen, while iron at the interface remains free of oxygen. Reactive deposition of CoO, with a thickness t CoO up to about 25 ML (1 CoO ML = 0.213 nm), was performed with the sample kept at 470 K by evaporating metallic Co in a pure O 2 atmosphere with partial pressure p O2 = 1 · 10 −4 Pa. 21 Magnetic hysteresis loops were acquired at room temperature on samples characterized by t CoO = 25 ML with the Magneto-Optical Kerr Effect (MOKE) apparatus described in Ref. 28 and are reported in Fig.…”

“…Preparation approaches different from that described in Ref. 21 (in particular different growth temperatures), produced samples that did not show multijump magnetic hysteresis loops.…”