Magneto-optical anisometry of ultrathin cobalt films

Abstract

The advantage of magneto-optics to measure magnetic anisotropy constants in ultrathin films exhibiting perpendicular spin anisotropy is reported. This is illustrated for Au/Co/Au sandwiches with Co layer thickness ranging from 8 to 15 Å. We stress the importance of preliminary measurements always necessary to define the (H∥,H⊥) region in which a homogeneous spin rotation occurs. These results confirm the existence of interface anisotropy and lead to its estimation Ks=0.56 erg/cm2 whereas the volumic term is shown to be Kv=7.5×106 erg/cm3.

Determination of intrinsic damping of perpendicularly magnetized ultrathin films from time-resolved precessional magnetization measurements

“…Under such conditions weaker torques which are usually neglected may become relevant 24,31 . These torques could possibly originate from dipolar or exchange coupling resulting in two magnon scattering processes or even in a breakdown into magnetic domains as described by Grolier et al 26 . From the limited data range at this angle, the damping could not be measured.…”

“…[4]. The TRMOKE measurement was carried Additionally, it is also possible that the lower signal to noise ratio observed for 1 H   may be due to a breakdown into domains with the almost in-plane applied magnetic field 26 .…”

The electron analogue to the Faraday rotation

“…• /nm is found for electrons, only 0.1 • /nm is found for photons [13]. This difference in the strength of the 'magneto-optic' phenomena arises because the electron spin couples directly 9.5 (3) with ∆E ex = constant.…”

Modification of Magnetic Properties of Pt/Co/Pt Films by Ga+ Ion Irradiation: Focused versus Uniform Irradiation

“…13). In the uniformly irradiated sputtered film, the PMA was described by the effective anisotropy field H ef f A , determined by analyzing rotational part of magnetization curves in crossed outof-plane and in-plane magnetic fields [39]. The PMA is found to be nearly constant with the fluence up to F ≈ 4 × 10 13 Ga + ions/cm 2 and decreases monotonously above (Fig.…”

“…Magnetic anisotropy in regions with perpendicular anisotropy was determined analyzing rotational part of magnetization curves in crossed out-of-plane and in-plane magnetic fields following procedure similar as was discussed in the work [39]. For the d Co = 3 nm sputtered film, the dependence of H ef f A with the Ga + ion fluence is depicted in Fig.…”