Unusually Large Magnetic Anisotropy in Electrochemically Deposited Co-Rich Co–Pt Films

Abstract

Co-rich Co-Pt films grown by electrodeposition from an amino-nitrite/citrate/glycine electrolyte onto Au(111) substrates apparently grow with a hexagonal structure, with its c-axis directed perpendicular to the surface. The films exhibit a perpendicular magnetic anisotropy (MCA) of the same order of magnitude as the shape anisotropy. Experimental estimates of the MCA result in a higher anisotropy than that reported for bulk materials of the same composition, but similar to values measured in films grown by vacuum methods at relatively high temperature, which partly consist of a high anisotropy, metastable orthorhombic Pmm2 phase. Comparison of valence band X-ray photoelectron spectroscopy measurements on electrodeposited films with density functional theory simulations of the electronic structure of the various reported Co(3)Pt structures support the notion that the films may consist of a mixture of the hexagonal and the Pmm2 structure.

Electrodeposition of Thin CoPt Films with Very High Perpendicular Anisotropy from Hexachloroplatinate Solution: Effect of Saccharin Additive and Electrode Substrate

“…Textured films of hcp CoPt alloys-without postannealing-have been obtained with high perpendicular coercivities up to 6000 Oe at thickness >100 nm. [13][14][15][16][17][18] However, these studies show that the perpendicular coercivities at the thickness of interest for BPM application (15-20 nm) appeared to be relatively low. Importantly, the formation of 10 nm thin CoPt nanodot arrays-deposited inside the nanopores with 10 nm diameters and moderate corcivities (1500-1700 Oe)-for application in ultra-high magnetic BPM was demonstrated recently.…”

“…18 The estimated values of K u for ∼15 nm thin CoPt films with 71 at % Co are shown in Table II, together with out-of-plane coercivity (H c , ⊥) and saturation magnetization (M s ) which was determined experimentally from measured magnetization and volume of CoPt films. The values of the uniaxial anisotropy constant K u and saturation magnetization of the Co 80 Pt 20 films shown in Table II …”

Direct Observation of Magnetocrystalline Anisotropy Tuning Magnetization Configurations in Uniaxial Magnetic Nanomaterials

“…To date, interfacial effects have been found to be the main contribution to the magnetic anisotropy in nanosized cobalt clusters embedded in niobium film, 1 while the perpendicular magnetic anisotropy can achieve the same order of magnitude of shape anisotropy in Co-rich Co−Pt film. 11 Besides, the existence of slow magnetic relaxation in one-dimensional cyanometalate complex 4 magnetic anisotropy by the electric field in ferroelectric polymer film was also reported. 8 However, how the crystal orientation and the additional degrees affect the magnetic anisotropy and the magnetization configuration remains unclear.…”

“…Magnetic anisotropy (MA) determines the magnetization configuration of magnetic materials and plays a critical role in many impacted applications including the magnetic recording, communication devices and spintronic devices. − High magnetic anisotropy is crucially demanded for the high stability of magnetic recording units. Numerous research on ferromagnetic bulk materials has demonstrated the dominant role of crystal structure and chemical composition in the magnetic anisotropy. − In comparison with bulk materials, low-dimensional magnetic nanostructures can offer additional degrees of freedom to tune the magnetic anisotropy through the modulation of size and morphology. − Therefore, the features of the nanostructured materials become more attractive in fundamental research and practical applications. To date, interfacial effects have been found to be the main contribution to the magnetic anisotropy in nanosized cobalt clusters embedded in niobium film, while the perpendicular magnetic anisotropy can achieve the same order of magnitude of shape anisotropy in Co-rich Co–Pt film .…”

“…Numerous research on ferromagnetic bulk materials has demonstrated the dominant role of crystal structure and chemical composition in the magnetic anisotropy. − In comparison with bulk materials, low-dimensional magnetic nanostructures can offer additional degrees of freedom to tune the magnetic anisotropy through the modulation of size and morphology. − Therefore, the features of the nanostructured materials become more attractive in fundamental research and practical applications. To date, interfacial effects have been found to be the main contribution to the magnetic anisotropy in nanosized cobalt clusters embedded in niobium film, while the perpendicular magnetic anisotropy can achieve the same order of magnitude of shape anisotropy in Co-rich Co–Pt film . Besides, the existence of slow magnetic relaxation in one-dimensional cyanometalate complex and the controllable magnetic anisotropy by the electric field in ferroelectric polymer film was also reported .…”