It is almost impossible to make samples without instrument. If you are interested to make thin films then the minimum and low cost techniques are spray pyrolsis, spin coater. Even if you can't afford the said techniques then you can prepare the solution of the desired materials using nitrates of the constituents element of final target, and dip the substrate in that solution in ultrasonic condition. Further, regarding spintronics related research, you can calculate the density of states and using the magnitude of density of states at Fermi level for both up (majority) and down Spin (minority) carriers, you can calculate the spin polarization. This is ofcourse an estimations of the parameter for making decisions to consider a material for spintronics application within the approximation of density functional theory based code. Later one good, as you don't need instrument, but, Computational facilities atleast a desktop or laptop needed with open dft codes like quantum espresso, kkr-cpa, spr-kkr, abinit, ELK-lapw, etc. Good luck

You should use Doctor blade coating methods. This method needs only a Doctor's blade. However, use this method you cannot coat uniformly.

The cheapest tools to make thin films without using expensive instruments are hand-held airbrush or hand held drawdown bars. You could get a good quality of films by adjusting your solution concentrations, solvents, and environmental factors such as temperature and humidity.