  Controlled spin transport in magnetic stacks is required to realize pure spin
current-driven logic and memory devices. The control over the generation and
detection of the pure spin current is achieved by tuning the spin to charge
conversion efficiency of the heavy metal interfacing with ferromagnets. Here,
we demonstrate the direct tunability of spin angular momentum transfer and
thereby spin pumping, in CoFeB/Pt stack, with interfacial magnetic anisotropy.
The ultra-low thickness of CoFeB thin film tilts the magnetic easy axis from
in-plane to out-of-plane due to surface anisotropy. The Ferromagnetic resonance
measurements are performed to investigate the magnetic anisotropy and spin
pumping in CoFeB/Pt stacks. We clearly observe tunable spin pumping effect in
the CoFeB/Pt stacks with varying CoFeB thicknesses. The spin current density,
with varying ferromagnetic layer thickness, is found to increase from 0.11 to
0.24 MA/m2, with increasing in-plane anisotropy field. Such interfacial
anisotropy-controlled generation of pure spin current can potentially lead to
next-generation anisotropic spin current-controlled spintronic devices.
