DETAILED DESCRIPTION OF THE INVENTION The poly(paraxylylene), poly(monochloroparaxylylene), and poly(dichloroparaxylylene) used in forming the protective layer of this invention have the following respective formulae: ##STR1## A protective layer of these polymers is formed by gas-phase, thermal decomposition vacuum evaporation.
In a preferred embodiment of the gas-phase thermal decomposition vacuum evaporation, cyclodiparaxylylene, Cl-substituted cycloparaxylene or a mixture thereof is decomposed thermally by heating to a temperature of from about 450.
degree.
C.
to 700.
degree.
C.
, and a gas flow of the paraxylylene radical vapor obtained is introduced onto the magnetic layer and cooled to a temperature lower than 100.
degree.
C.
to form a polymer or copolymer film.
To achieve the desired protecting effect and to prevent output drop that is caused by spacing loss due to the gap between the magnetic recording surface and magnetic head, the protective layer generally has a thickness of from about 0.
002 to 0.
3 .
mu.
m, and preferably from 0.
005 to 0.
2 .
mu.
m.
The thin ferromagnetic metal film used in this invention is prepared by vapor deposition or plating of a ferromagnetic metal such as iron, cobalt or nickel, or a ferromagnetic alloy such as Fe-Co, Fe-Ni, Fe-B, Co-Ni, Fe-Si, Fe-Rh, Fe-V, Co-P, Co-B, Co-Si, Co-V, Co-Y, Co-La, Co-Ce, Co-Pr, Co-Sm, Co-Mn, Co-N, Fe-N, Fe-Co-Ni, Co-Ni-P, Co-Ni-B, Co-Ni-Ag, Co-Ni-Nd, Co-Ni-Ce, Co-Ni-Zn, Co-Ni-Cu, Co-Ni-Hg, Co-Ni-W, Co-Ni-Re, Co-Mn-P, Co-Fe-P, Co-Zn-P, Co-Pb-P, Co-Sm-Cu, Co-Fe-N, Co-Ni-Zn-P, Co-Ni-Fe-B, Co-Ni-Fe-P, or Co-Ni-Mn-P.
Vapor deposition is a technique wherein an element or a compound containing that element is deposited on the substrate in the form of vapor or ionized vapor, and variations of this technique include vacuum evaporation, sputtering, ion plating, and chemical vapor deposition.
Plating refers to a technique wherein an element or a compound containing that element is deposited from a liquid phase by electroplating or electroless plating
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