Tuned edge profile of a disk substrate for use in magnetic recording media

A magnetic recording disk, the disk comprising:

• a first surface extending along a first plane;
• a second surface extending along a second plane parallel to the first plane;
• a disk thickness between the first surface and the second surface, measured along a first direction substantially normal to the first surface;
• an edge surface disposed along a perimeter of the disk and between the first surface and the second surface, wherein the edge surface extends along a third plane substantially perpendicular to the first surface;
• a conductive layer disposed on the first surface and the edge surface;
• a first chamfer disposed between the first surface and the edge surface;
• and
• a second chamfer disposed between the second surface and the edge surface,
• wherein a length of the edge surface measured along the first direction is between 40% and 80% of the disk thickness,
• wherein the disk comprises a non-conductive material, and
• wherein a contact resistance between the edge surface and a point on the first surface is below 200 Ohms.

A method of fabricating a disk for a magnetic recording apparatus, the method comprising:

• providing a disk comprising an annulus shape and comprising:
• a first surface extending along a first plane;
• a second surface extending along a second plane parallel to the first plane;
• and
• a disk thickness between the first surface and the second surface, measured along a first direction substantially normal to the first surface;
• removing material from a first perimeter corner of the disk to form a first chamfer;
• and
• removing material from a second perimeter corner of the disk to form a second chamfer and an edge surface disposed between the first chamfer and the second chamfer, wherein the edge surface is disposed and between the first surface and the second surface, wherein the edge surface extends along a third plane substantially perpendicular to the first surface, wherein a length of the edge surface measured along the first direction is between 40% and 80% of the disk thickness, and
• wherein the edge surface comprises an edge profile with a convex shape such that a cross section of the edge surface, taken along a plane perpendicular to the first surface and along a diameter line of the disk, comprises the convex shape without a flat portion.

A magnetic recording disk substrate, the disk substrate comprising:

• a first surface extending along a first plane;
• a second surface extending along a second plane parallel to the first plane;
• a disk substrate thickness between the first surface and the second surface, measured along a first direction substantially normal to the first surface;
• an edge surface disposed along a perimeter of the disk substrate and between the first surface and the second surface, wherein the edge surface extends along a third plane substantially perpendicular to the first surface;
• a first chamfer disposed between the first surface and the edge surface;
• and
• a second chamfer disposed between the second surface and the edge surface,
• wherein a length of the edge surface measured along the first direction is between 40% and 80% of the disk substrate thickness, and
• wherein the edge surface comprises an edge profile with a convex shape such that a cross section of the edge surface, taken along a plane perpendicular to the first surface and along a diameter line of the disk, comprises the convex shape without a flat portion.