Did you mean spin injection? Probably what I understand from your question is that spin pumping may refer to spin current. Conventional electronics is based on the charge state. For example logic 1 refers to 5 V and logic 0 may be 0 V. But if you include the quantum mechanical property of electron, ie. spin, it has many states leads to no. of logic operation, thereby increasing the data manipulation/storage. Spin state may be either parallel or anti parallel (u can now imagine how many allowed state exist between 180 deg of rotation!) The current produced by the spin may be referred to spin current. If you inject an electron into a FM, it probably aligns with respect to the FM and by choosing another FM through a metal/insulator/semiconductor, u can design a spin valve type transistor. Thus you can manipulate/store no.of data in the form spin states.

Let's have a bilayer Ferro/Normal metal typicaly NiFe/Cu.Combining a fix strong field and RF ossillating transverse film you will induced a precession of the magnetization in the ferromagnetic film. This precession will induced a spin accumulation (imbalance of chemical potential for spin up and spin down) in the Cu thin film. This is Spin Pumping.