Influence of the Cr and Ni concentration in CoCr and CoNi alloys on the structural and magnetic properties

Abstract

a b s t r a c tThe crystalline and magnetic properties of micron thick magnetron sputtered Co 1 À x Cr x and Co 1 À x Ni x alloy films are analyzed in the view of their implementation as semi-hard magnets. All of the tested films crystallize in an hcp lattice, at least up to 35 at% of alloying elements (Cr or Ni). The structural study shows that the ratio of hcp phase with [0001] axis orientated perpendicular to the film as compared with in-plane orientation increases (resp. decreases), when Ni (resp. Cr) concentration increases independently of the post-annealing temperature. The orientation of the magnetization results from the competition between the demagnetization field which tends to align the magnetization in plane and the crystalline anisotropy which tends to maintain the magnetization along the [0001] axis. Interestingly, we find that, although Co and Ni are very similar atoms, Co 1 À x Ni x alloys crystalline anisotropy can be strongly increased and reach up to twice the anisotropy of the best Co 1 À x Cr x alloy, while maintaining a magnetization at saturation above 1200 kA/m. The thermal stability of the structural and magnetic properties of both alloys is demonstrated for an annealing temperature up to 300°C.

Microstructural and Morphological Characterization of the Cobalt-Nickel Thin Films Deposited by the Laser-Induced Thermionic Vacuum Arc Method

“…If we consider the squareness of the in-plane field hysteresis loop defined as the ratio between the remanent magnetization and saturation (M r /M s ), the obtained value is around 0.15. This value is smaller than the 0.4 obtained in the Co 1−x Ni x with x = 25%, 1 µm-thick film of CoNi alloys deposited using the sputtering technique [54]. The coercive field is slightly lower than that in the case of Co 1−x Ni x for all Ni at.% concentrations for which the coercive field is over H c = 100 Oe.…”

Aerosol-based functional nanocomposite coating process for large surface areas

“…The second way to adjust the [np]/[matrix] ratio is related to the matrix deposition rate. The deposition rate is generally proportional to the electrical power injected in the cathode [57][58][59] . As an example, Fig.…”

Photoelectrical performances of semiconductor-based devices having CoFe and CoFeNi magnetic interlayers

“…The inclusion of some elements such as copper (Cu) and Ni in the synthesized thin films can lead to improvements in corrosion resistance and a decrease in coercivity [19]. For this purpose, the magnetic and structural properties of alloyed films in different combinations such as CoFeNi, CoFeAlN, CoFeCu, CoNi, and FeCoTiN have been investigated by many researchers [20][21][22][23][24][25]. Similar to CoFe, CoFeNi alloys exhibit high saturation magnetization, which is beneficial for magnetic applications [26,27].…”