Antiferromagnetic coupling in fcc Fe overlayers on Ni/Cu(100)

Abstract

Magnetic properties of ultrathin fcc Fe overlayers on Ni/Cu͑100͒ have been determined to study the influence of a magnetic interface. Three regions of different magnetic behavior are distinguished by magneto-optic Kerr ellipsometry, in line with previous studies of Fe/Co/Cu͑100͒ and Fe/Ni/Cu͑100͒. These magnetic states are closely related to the film structure. Above 10 monolayers ͑ML͒, the iron films are homogeneously magnetized and adopt the bcc phase. Very thin films up to 2.5 ML are homogeneously magnetized as well but show an fcc structure in conjunction with a (4ϫ1) reconstruction. The most complex magnetic properties characterize Fe films between 5 and 10 ML. In this thickness range the iron films are not homogeneously magnetized. Instead ferromagnetism is only observed at the Fe film surface and the Fe/Ni film interface. The surface magnetization is apparently correlated with an enlarged atomic volume at the surface and a (2ϫ1) surface reconstruction. Additionally, the magnetic Ni substrate induces ferromagnetic order in the Fe film at the Fe/Ni interface. The coupling of the two ferromagnetic portions of the film shows a strong temperature dependence. This is attributed to the temperature dependence of the bilinear and biquadratic exchange coupling. At low temperature an antiferromagnetic coupling between the two ferromagnetic portions is observed. With increasing temperature this is followed by a canted spin arrangement and finally a ferromagnetic coupling. ͓S0163-1829͑99͒07041-1͔

Structure, magnetic and Mössbauer studies of mechanically alloyed Fe–20wt.% Ni powders

“…This system also presents a rich phenomenology such as the Invar [4] and Permalloy [5] properties. In order to extend even more such properties, nanostructured FeNi alloys have been produced according to different methods as, e.g., thermal evaporation [6], electrodeposition [7] and metal-plasma reaction [8] Among these methods, mechanical alloying is one that allows a nanostructured state to be obtained [9][10][11][12]. It is an intensive energy process of mechanical grinding for the preparation of alloyed powders or composites in powder form [13,14].…”

Media effects on nanobrass arc fabrications

“…Changing the composition of these nanoalloys can drastically impact their properties (such as magnetic strength, conductivity, and surface chemistry), so careful attention must be paid to the synthetic methods and control of morphology. In recent years, many methods have been developed for the preparation of nanoalloy materials including: Metal evaporation, grinding of bulk metal, sputtering, organometallic precursor decomposition [18,19], ball milling (BM) [20], solution phase metal salt reduction [21,22], crystallization of noncrystallinestate [23], pulsed electro deposition [24,25], laser vaporization controlled condensation (LVCC) [26], sonochemical method [27,28], mechanical synthesis [29], template synthesis [30], ␥-ray irradiation [31], metal carbonyl pyrolysis [32], sandblast-annealing [33], laser ablation [34], and co-hydrogenolysis [35]. In particular, colloids of nanobrass alloys (␣/␤-CuZn) as well as colloidal solutions of nanocopper are obtained by co-hydrogenolysis of [CpCu(PMe 3 )] and [ZnCp * 2 ] in the presence of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) [35].…”

Nanocrystalline FexNi1−x (x≤0.65) alloys formed by chemical synthesis

“…The FeNi system presents a complex phase diagram [3] and a rich phenomenology [4,5] and for this reason several methods to produce FeNi alloys in nanometric form have been utilized: mechanical alloying [6][7][8][9], thermal evaporation [10], decomposition of organic metal salts [11], electrodeposition [12][13][14] and metal-plasma reaction [15] among others.…”