Enhancement of the magnetic anisotropy of Co clusters by Au capping

Luìs, Fernando; Bartolomé, J.; Bartolomé, Fernando; Martinez, M.J.; Garcı́a, L. M.; Pétroff, F.; Deranlot, C.; Wilhelm, F.; Рогалев, А.

doi:10.1063/1.2172217

Cited by 20 publications

(12 citation statements)

References 22 publications

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“…It is well known that an induced polarisation of Au capping layers occurs due to the interaction with the magnetic Co [19]. This observation, combined with the much reduced coercivity from either uncapped 4-atom wide wires or 1.3ML of Co on Pt(997) [17], is indicative that the Au capping has indeed greatly modified the magnetic anisotropy of the system, as has been observed previously in capped Co spherical clusters [4,20,21]. However, unlike the previous observations which were for spherical particles, the capping can be seen to induce a preferred orientation for the easy axis of magnetization .…”

Section: Resultssupporting

confidence: 58%

X‐ray magnetic circular dichroism and reflection anisotropy spectroscopy Kerr effect studies of capped magnetic nanowires

Cunniffe

McNally

Liberati

et al. 2010

Physica Status Solidi (b)

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Aligned Co wires grown on Pt(997) under ultra-high vacuum conditions have been capped successfully by the epitaxial growth of Au monolayers (ML) at room temperature. The samples were kept under vacuum except when transferring between apparatus or when making some of the measurements. No degradation of the Co wires was detected during the measurements. The magneto-optic response of the system was measured using xray magnetic circular dichroism (XMCD) at the Co L 2,3 edge and reflection anisotropy spectroscopy (RAS) at near-normal-incidence, which is sensitive to the normal component of the out-of-plane magnetization via the Kerr effect (MOKE). Capping the wires significantly impacts their magnetic properties. Comparison of the magnetooptic response of the system at x-ray and optical energies reveals small differences that are attributed to the induced moment in the Pt substrate and Au capping layer not picked up by the element specific XMCD measurements.. The sensitivity of RAS-MOKE is sufficient to allow the determination of the easy axis direction of the capped wires to within a few degrees. The results for a 6-atom-wide Co wire sample, capped with 6 ML of Au, are consistent with the capped wires possessing perpendicular magnetization.

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Section: Resultssupporting

confidence: 58%

X‐ray magnetic circular dichroism and reflection anisotropy spectroscopy Kerr effect studies of capped magnetic nanowires

Cunniffe

McNally

Liberati

et al. 2010

Physica Status Solidi (b)

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“…In fact, D values agree well with those of clusters in alumina. In the case of Au [15], we observe that magnetic properties are independent of the thickness of the capping layer, between 1.5 and 6 nm. Samples are usually made by piling up a number N of these Co/Al…”

mentioning

confidence: 88%

Tuning the magnetic anisotropy of Co nanoparticles by metal capping

et al. 2006

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The magnetic anisotropy of Co clusters with diameters ranging from 1.1 nm to 4.5 nm turns out to be significantly larger than in bulk and strongly increasing with decreasing cluster size. The dominating role of the surface can be used to modify the anisotropy by changing the electronic properties of the matrix surrounding the clusters. We find that capping the clusters by a metallic (Cu and Au) layer significantly enhances the anisotropy, thus also stabilizing the magnetization against thermal fluctuations. The observed anisotropy enhancement is attributed to the bonding of the Co 3d electrons to the conduction band of the capping layer, which depends on the electronic band structures of both metals.

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“…Binary 3d-5d clusters can be a challenging material in this respect. For example, there are observations that 4d and 5d elements like Rh, Pt and Au, which are nonmagnetic in bulk phase, attain significant moments when alloyed with 3d transition metals like Fe, Co or Ni [23,24,25,26].…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties of small Pt-capped Fe, Co, and Ni clusters: A density functional theory study

et al. 2010

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Theoretical studies on M 13 (M = Fe, Co, Ni) and M 13 Pt n (for n = 3, 4, 5, 20) clusters including the spin-orbit coupling are done using density functional theory. The magnetic anisotropy energy (MAE) along with the spin and orbital moments are calculated for M 13 icosahedral clusters. The angle-dependent energy differences are modelled using an extended classical Heisenberg model with local anisotropies. From our studies, the MAE for Jahn-Teller distorted Fe 13 , Mackay distorted Fe 13 and nearly undistorted Co 13 clusters are found to be 322, 60 and 5 µeV/atom, respectively, and are large relative to the corresponding bulk values, (which are 1.4 and 1.3 µeV/atom for bcc Fe and fcc Co, respectively.) However, for Ni 13 (which practically does not show relaxation tendencies), the calculated value of MAE is found to be 0.64 µeV/atom, which is approximately four times smaller compared to the bulk fcc Ni (2.7 µeV/atom). In addition, MAE of the capped cluster (Fe 13 Pt 4 ) is enhanced compared to the uncapped Jahn-Teller distorted Fe 13 cluster.

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Enhancement of the magnetic anisotropy of Co clusters by Au capping

Cited by 20 publications

References 22 publications

X‐ray magnetic circular dichroism and reflection anisotropy spectroscopy Kerr effect studies of capped magnetic nanowires

X‐ray magnetic circular dichroism and reflection anisotropy spectroscopy Kerr effect studies of capped magnetic nanowires

Tuning the magnetic anisotropy of Co nanoparticles by metal capping

Magnetic properties of small Pt-capped Fe, Co, and Ni clusters: A density functional theory study

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