Preannealing effect on ordering transformation and magnetic properties of CoPt thin films

Abstract

Single layer CoPt thin films with thicknesses from 30to100nm were sputtered on glass substrates. A preannealing at 250°C for 80min was applied to the samples, before ordering treatment at 700°C for 10min. This preannealing process resulted in a 33%–65% decrease in coercivity and 23%–55% decrease in volume fraction of order phase f0. Results of morphology investigation showed that the preannealing increases the surface roughness, which mainly results from the elimination of defects. Structural results further suggest that the eliminated defects are mostly low dimensional, such as dislocations or vacancies. It can thus be concluded that those low dimensional imperfections in the CoPt films play an enhancing role in ordering transformation process.

Early-stage ordering in in-situ annealed Fe51Pt49 films

“…The gradual increase in surface roughness of films grown in Regime I can be mainly considered due to the in-plane strain relaxation as mentioned above. A similar phenomenon has been observed in binary CoPt thin films pre-annealed at low temperature (250 1C) for longer time (80 min) by using AFM techniques [47]. From Regime I to II, thermal energy consumed in film growth can no longer account for the rougher surface; instead, it makes possible the nucleation of ESO observed by EXAFS results; noting that, the samples deposited at 250 1C exhibit rougher surface, thereafter become smoother in accordance with the process of ESO.…”

Synthesis of CoxPt1−x alloy nanoparticles of different phase by micellar technique and their properties study

“…have been widely studied [17][18][19]. For such kind of preparation very costly instruments are required in most of the cases, in addition to that controlling the size and ratio of constituent materials in the alloy nanoparticles and optimization of the manufacturing procedure are very difficult and in some cases are not possible.…”

“…CoPt alloys have various crystalline phases such as L1 0 , L1 2 , L1 1 , m-DO 19 and FCC structures and they have different applications [8][9][10][11]. These phases can be obtained under specific experimental conditions, with specific composition of constituent elements.…”

Nanostructured magnetic CoPt thin films synthesis using dense plasma focus device operating at sub-kilojoule range

“…In particular, the interest in alloy magnetic particles is aimed at lowering the particle size and getting a uniform particle distribution for potential application in high density storage. This potential application depends on the capability to prepare nanostructured CoPt alloy on a substrate with the highly anisotropic L1 0 -ordered structure in which thermal treatment is usually required to convert the as-deposited, chemically disordered, magnetic soft fcc phase to a chemically ordered magnetic hard L1 0 phase [3][4][5]. 1 Author to whom any correspondence should be addressed.…”