Tribological troubles and tape-curling of perpendicular magnetic recording tapes are critical for their practical use. Thin films of a wear resistant and electrically conductive Fe-Mo-B based alloy were prepared on plasma-free tape substrates by the facing targets sputtering (FTS) method for applying them as protective layers in the magnetic tapes. The films were perfectly amorphous, very flexible and almost non-magnetic. The alloy targets for these films contained molybdenum atoms at a concentration as high as 24 at%. The Mo atomic weight is higher than that of working gas atoms Ar and Kr. Accordingly, not only Ar but also Kr atoms were recoiled from the target planes and then bombarded the growing layers to cause large compressive stress in the deposited films. Therefore, these protective films must be very thin to avoid tape-curling. Protective films as thin as 100 Å could largely reduce the dynamical friction coefficients of the surfaces of magnetic tapes owing to the hardness of their ceramic phase. In addition to this merit they possessed electrical resistivity as small as 1.2×10-4 Ω·cm. owing to their metallic binder phase. Consequently they are applicable as protective layers of curl-free magnetic tapes.