Thin film magnetic recording medium with controlled grain morphology and topology

DETAILED DESCRIPTION Referring now the FIGURES and to FIG.
1A in particular, there is shown in accordance with the present invention a substrate 10 such as silicon dioxide, glass, polymer or thin coating thereof on any suitable non-magnetic storage disk material.
The substrate is selected to be non-wettable by liquid metals.
As used in the context of this invention, the term non-wettable refers to the break up of a liquid uniformly deposited film to form a distribution of disconnected liquid metal features due to the lack of wetting or interaction between a substrate and the liquid metal.
Deposited upon the substrate is an underlayer of a transient liquid metal 12 such as gallium, indium, tin, bismuth, lead, cadmium, mercury, selenium, tellurium and their alloys with other elements, including silver, palladium, platinum or gold as well as binary or ternary compounds of the transient liquid metals themselves.
The preferred transient liquid metals are gallium, indium and tin.
The average film 12 thickness is the range between approximately 25.
ANG.
and 300.
ANG.
, preferably in the range between 25.
ANG.
and 100.
ANG.
.
The term transient liquid metal layer refers to the temporary existence of the liquid metal layer, until a deposition of a sufficient quantity of a magnetic alloy material results in the dissolution and reaction of the liquid metal in the magnetic alloy, with the substantially complete disappearance of the liquid phase from the magnetic medium structure.
As a result, in the final magnetic medium there is no distinct transient liquid metal film layer, but rather there is an intergranular segregation of such metal, as shown in FIG.
1B.
The transient liquid metal layer is applied to the substrate while the substrate is maintained at a temperature in excess of the melting point of the transient liquid metal.
In the example of a gallium film, the substrate is held at a temperature above approximately 30.
degree.
C.
during transient liquid metal deposition.
Due to the poor wetting of the substrate by the liquid metal, the liquid metal forms spherical features as shown in FIG