Interface and Volume Anisotropy of MBE-Grown Co/Pt (111), (110) and (001) and Sputtered CO/Pt Multilayers

Abstract

A quantitative determination of interface (Ks) and volume anisotropy (Ko) constants of MBE and sputtered Co/Pt multilayers is reported. Torque and VSM magnetometry were used to determine the total average anisotropy and the room temperature magnetization of four different series of films with varying Co thickness and nearly constant Pt thickness. All films were characterized with X-ray diffraction and X-ray fluorescence, allowing the determination of the "magnetic" volume with good accuracy. Both Ks and KWf are found to be orientation dependent. We find the following results for MBE films grown on Ag buffered GaAs substrates and highly < 111 > textured films, grown on etched SiNx buffers: (111)Ks =0.92mJ/m 2 , Kveff=-l.l IMJ/m 3 sputtered (110) Ks=0.42mJ/m 2 , Kveff=-l.95MJ/m 3 MBE (001)Ks=0.59mJ/m 2 , Kveff=-5.98MJ/m 3 MBE The [l10]-oriented MBE films show in addition a large (intrinsic) in-plane anisotropy constant K -'-3MJ/m 3 , which is found to be independent of the Co thickness.[100] is the easy and [1I0] the hard in-plane direction.

Morphological stripe-bubble transition in remanent magnetic domain patterns of Co/Pt multilayer films and its dependence on Co thickness

“…At some critical thicknesses t Co , the magnetization changes its preferential orientation due to the predominance of shape anisotropy over the magnetocrystalline and interface anisotropies, and vice versa. If the thickness t Co of a single Co layer is below ∼16 Å, 1 the interface anisotropy overcomes the shape anisotropy, resulting in an OOP magnetization independent of the number of repeats N [4,7,[33][34][35][36][37][38][39][40]. However, if the Co thickness is larger than ∼16 Å, the shape anisotropy, which is constant and equal to 2πM 2 S in the low thickness regime (where M s is the magnetization at saturation) [41], starts to dominate the interface anisotropy, which scales with the inverse thickness [7], and the magnetization turns IP.…”

Magnetic anisotropy and spin reorientation in Co/Pt multilayers: Influence of preparation

“…The use of ECR sputter deposition, however, is known to result in highly /111S-textured Pt films with smooth surfaces [7]. That means the increase of interface anisotropy in the combined ECR/magnetron fabricated films compared to the magnetron-sputtered films must be appointed to better crystal orientation of the seed layer as the epitaxial growth of hcp [0 0 0 1] Co is best for Pt(111) [2]. Additionally, smoother interfaces support higher interface anisotropies [16].…”

“…In general, the highest perpendicular anisotropy is obtained for epitaxial growth [2][3][4] at best on single crystal surfaces [3,4]. Nowadays, the multilayers are mostly fabricated via magnetron sputtering, a growth technique that is easy to apply.…”

Ion induced magnetization reorientation in Co/Pt multilayers for patterned media

“…This assumes a maximal, intrinsic interface anisotropy value of K S ≅ 1 erg/cm 2 (100%) (see e.g. results found in highly perfected MBE Co/Pt films [6]). Interestingly, these are exactly the doses needed to trigger spin reorientation in the present samples.…”