Surfactant effect in heteroepitaxial growth: The Pb-Co/Cu(111) case

Gómez, Liliana; Ferrón, J.

doi:10.1103/physrevb.64.033409

Cited by 18 publications

(12 citation statements)

References 22 publications

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“…It has been demonstrated in the literature that by using surfactants, the problem of asymmetric interfaces can be reduced to a large extent [16][17][18][19][20][21][22]. The prerequisites for a material to qualify as a surfactant is its optimal quantity and a low as compared to other elements present in the multilayer.…”

Section: Introductionmentioning

confidence: 99%

Surfactant controlled interfacial alloying in thermally evaporated Cu/Co multilayers

Amir

Gupta

2012

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 99%

Surfactant controlled interfacial alloying in thermally evaporated Cu/Co multilayers

Amir

Gupta

2012

Journal of Alloys and Compounds

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“…Further studies [23][24][25][26][27] have also demonstrated the beneficial effect of Pb as surfactant in evaporated and MBE-grown FM/NM multilayers. Several other surfactant elements such as Bi, [26][27][28][29][30] Ag, [31][32][33][34][35] Au 36 and In 37 have been similarly found to induce layer quality improvement for physically deposited multilayers.…”

Section: D332mentioning

confidence: 99%

Influence of Ag Additive to the Spacer Layer on the Structure and Giant Magnetoresistance of Electrodeposited Co/Cu Multilayers

Neuróhr

Péter

Pogány

et al. 2015

J. Electrochem. Soc.

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In order to explore the possible surfactant effect of Ag on the formation of electrodeposited multilayers, Co/Cu(Ag) multilayers were prepared by this technique and their structure and giant magnetoresistance (GMR) were investigated. The multilayers were deposited from a perchlorate bath with various amounts of Ag + ions in the solution for incorporating Ag atoms into the multilayer stack. Without Ag addition, secondary neutral mass spectroscopy (SNMS) indicated a well-defined composition modulation of the undermost Co/Cu bilayers. However, already at an Ag content as low as 1.8 at.% incorporated, SNMS showed a deterioration of the periodic multilayer structure. In agreement with the SNMS results, superlattice satellites were visible in the X-ray diffraction (XRD) patterns of the multilayers with up to 0.3 at.% Ag. The satellites were, however, very faint even for multilayers without Ag addition, indicating that the multilayers have high interface roughness and/or poor periodicity. In the absence of Ag and at the smallest Ag content investigated by XRD, a strong central multilayer peak and the weak superlattice satellites were complemented by weak diffraction maxima from non-periodic Co and Cu domains. In the Co/Cu(Ag) multilayer containing about 25 at.% Ag, i.e., nearly as much as Cu, XRD found a separate Ag(Cu) phase. In spite of the imperfect layered structure, a multilayer-type GMR behavior was observed in all samples up to about 10 at.% Ag incorporated in the multilayer stack. The GMR magnitude increased for Ag contents up to about 1 at.%, which implies that a small amount of Ag may have a beneficial effect through a slight modification of the layer growth and/or interface formation. However, for higher Ag contents beyond this level, the GMR was reduced in line with the structural degradation revealed by XRD and SNMS. For the highest Ag contents (above about 10 at.%), the GMR exhibited a behavior characteristic of a granular magnetic alloy, in agreement with the results of the structural study. One of the major obstacles hindering the realization of a high giant magnetoresistance (GMR) in electrodeposited (ED) ferromagnetic/non-magnetic (FM/NM) multilayers is that the nonmagnetic spacer layer cannot be electrodeposited as pinhole-free for layer thicknesses which are required to achieve high GMR and an oscillatory GMR behavior. 1 Sputtered Co/Cu multilayers 2-4 exhibit an oscillatory GMR and a room-temperature GMR of about 50% and 20% at about 1 and 2 nm Cu layer thicknesses, respectively. At these particular spacer thicknesses, a strong antiferromagnetic (AF) exchange coupling exists between the adjacent magnetic layers. It gives rise then to a large GMR effect since the AF coupling ensures an antiparallel alignment of the magnetizations of the neighboring magnetic layers in zero magnetic field. For spacer thicknesses between these so-called AF maxima, the exchange coupling is predominantly ferromagnetic. Thus, due to the parallel alignment of the layer magnetizations even in zero magnetic field, no GMR eff...

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“…Recently, a few models were proposed to describe the growth behavior in SME. [13][14][15][16][17][18] For instance, Wu et al constructed a reactionlimited aggregation ͑RLA͒ model 14 which includes the following atomistic processes: diffusion of adatoms on the surfactant terrace and exchange of adatoms with their underneath surfactant atoms for nucleation ͑seed exchange͒ or for becoming incorporated at the existing island edges ͑aided exchange͒. Using kinetic Monte Carlo ͑KMC͒ simulations, the model reproduces the fractal-to-compact island shape transition as observed experimentally in Ge growth on Pb-covered Si͑111͒.…”

Section: Introductionmentioning

confidence: 99%

Nucleation transition and nucleus density scaling in surfactant-mediated epitaxy

2005

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A model of submonolayer epitaxial growth mediated by a monolayer of surfactant is studied, where exchange of adatoms with their underneath surfactant atoms is reversible; i.e., an exchanged adatom can reexchange with the lifted surfactant atom to return to the top of the surfactant layer when the substrate temperature is high enough. A rate equation analysis shows that island nucleation governed by the reexchanging-controlled surface diffusion obeys a scaling law, which connects the nucleation density with the rates of the deposition, surface diffusion, exchange, and reexchange process. Our model system reveals distinct nucleation transitions due to the activated exchange and reexchange, and the nucleation density as a function of temperature exhibits a characteristic N shape with a minimum and a maximum, which define the transition temperatures. The analytical results are confirmed by comparison with kinetic Monte Carlo simulations.

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Surfactant effect in heteroepitaxial growth: The Pb-Co/Cu(111) case

Cited by 18 publications

References 22 publications

Surfactant controlled interfacial alloying in thermally evaporated Cu/Co multilayers

Surfactant controlled interfacial alloying in thermally evaporated Cu/Co multilayers

Influence of Ag Additive to the Spacer Layer on the Structure and Giant Magnetoresistance of Electrodeposited Co/Cu Multilayers

Nucleation transition and nucleus density scaling in surfactant-mediated epitaxy

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