Stabilization of Co/Pt(111) against surface alloying by Ag overlayers

Abstract

The initial growth and annealing effects of Ag ultrathin films on the surface of 1 ML Co/Pt͑111͒ were investigated by low-energy electron diffraction ͑LEED͒, Auger electron spectroscopy, and ultraviolet photoelectron spectroscopy. The Ag atoms are in a layer-by-layer growth only of the first two atomic layers. Within these coverages, the adatoms of Ag are in instability when the substrate starts Co-Pt alloying. The intensity of the specular beam of LEED versus temperature increases dramatically after the alloy formation is complete. The temperature of the formation of the Co-Pt alloy becomes higher as the coverage of Ag increases. These unusual phenomena are, to our knowledge, the first observation in the systems containing three-component ultrathin films. The stress of overlayers causing the change of the alloying temperature is proposed.

Ag-induced spin-reorientation transition of Co ultrathin films on Pt(111)

“…17 Ag atoms deposited on the 1-3-ML Co/Pt͑111͒ initially grow 2 ML in a layerby-layer mode and then change to the three-dimensional ͑3D͒ island growth mode. 18 The polar and longitudinal Kerr signals versus magnetic field H for different thicknesses of Co on Pt͑111͒ are shown in Fig. 1.…”

The role of the CO adsorption on Pt monolayers supported on flat and stepped Au surfaces: a density functional investigation

“…Ultrathin metal lms composed of one or few layers supported on at or stepped transition-metal (TM) surfaces have been considered as promising catalysts for several reactions due to the possibility to tune their chemical activity by controlling substrate strain, composition, and ligand effects. [1][2][3] TM layers supported on TM surfaces, such as (111), (100), and (110), have been widely studied, e.g., Fe, Co, Ni, and Pd on Au(111) and Au(110), [4][5][6][7][8][9] Co/Ag(111), 7 Co and PtAu on Pt(111), 10,11 Pt and Au on Ni(110), [12][13][14] Pt/Ni(111), 15 Pt and Au on Ru(0001), 16 Ag and Au on Cu(100), 17 Au/Cu(110), 18 Ag and Au on Pd(100), 17 and Au/Ir(111). 19 Among those systems, Pt layers supported on Au surfaces have attracted a great interest, in particular, for the designing of high performance fuel cell electrocatalysts to improve oxygen reduction reactions.…”

Enhancement of magneto-optical Kerr effect for Co ultra-thin film on Pt(111) with Ag buffer layer

“…4, curve (1) is the coercivity measured at room temperature as a function of annealing temperature T A for 1 ML Co/1 ML Ag/Pt(1 1 1). We kept T A p735 K, because Ag overlayer can be desorbed when T A > 750 K [16]. H c increases rapidly when T A is between 400 and 600 K, and keep constant when 600 KoT A o650 K. Note that the atomic exchange between Ag and Co occurs when 400 KoT S o600 K as shown in Fig.…”