Magnetic anisotropy ofCoxPt1−xclusters embedded in a matrix: Influences of the cluster chemical composition and the matrix nature

Abstract

We report on the magnetic properties of Co x Pt 1−x clusters embedded in various matrices. Using a careful analysis of magnetization curves and ZFC susceptibility measurements, we determine the clusters magnetic anisotropy energy (MAE) and separate the surface and volume contributions. By comparing different chemical compositions, we show that a small amount of Pt (15 %) induces an important increase in the volume anisotropy with respect to pure Co clusters, even in chemically disordered fcc clusters. Comparing the measurements of clusters embedded in Nb and MgO matrices, we show that the oxide matrix induces an important increase of the surface MAE attributed to the formation of an antiferromagnetic CoO shell around the clusters.

Magnetization reversal of a single cobalt cluster using a RF field pulse

“…In this case, K eff corresponds to the energy barrier to overcome to reverse the particle magnetization i.e., to the MAE in zero magnetic field. In order to give a quantitative evaluation of the matrix influence on the magnetic anisotropy energy, the zero-field-cooled response of a monodisperse clusters assembly with a random orientation of the anisotropy axis, can be described as a function of temperature [7,8].…”

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

“…Theoretically, there have been several studies on magnetic anisotropy for supported clusters [27,28,29,30,31,32,33], whereas studies on small free clusters are still limited [34,35,36,37,38]. The motivation for the present study is that icosahedral clusters for M 13 are known to be very stable, [6,12,39] and the alloying of 3d transition metals with Pt results in large magnetic anisotropy as well as orbital moment.…”

Structural and magnetic properties of granular Co-Pt multilayers with perpendicular magnetic anisotropy

“…Other routes recently used for this purpose consist in producing alloyed particles, so that the intrinsic source of anisotropy is modified [7][8][9][10][11][12]. In this respect, we have recently explored the introduction of high spin-orbit nonmagnetic elements and * aifigueg@gmail.com induce their alloying with Co.…”

“…In fact, the production of Co-Pt alloys is one of the preferred routes currently used in nanoparticles and thin films to increase their magnetic anisotropy [8][9][10]. For example, CoPt NPs embedded in different matrices show enhanced magnetic anisotropy with respect to the Co particles [9,10,18,19].…”