An ink-printed substrate includes a substrate and water-based ink composition printed on the substrate, and has a Crockfastness-Loss-to-Density Ratio of about 1.0 to about 6.0.

A magnetic recording medium includes a substrate, a seed layer, an under layer, and a perpendicular recording layer having a granular structure. (Ms.Math..sup.1.5(1Rs).sup.0.33), Ms, and satisfy (Ms.Math..Math..sup.1.5(1Rs).sup.0.33)0.1 [.Math.emu.Math.(mm).sup.1.5], Ms450 [emu/cc], and 1.2. In the above formulas, Ms indicates a saturated magnetization amount, indicates the gradient of a M-H loop around a coercive force Hc, indicates the thickness of the perpendicular recording layer, and Rs indicates a squareness ratio.

There is provided a magnetic recording medium including a surface having a longitudinal direction and a lateral direction. An arithmetic average roughness Ra, a ratio PSD.sub.MD,short/PSD.sub.TD,short, and a ratio PSD.sub.MD,long/PSD.sub.TD,long on the surface satisfy Ra3.0 nm, PSD.sub.MD,short/PSD.sub.TD,short0.65, and 1.3PSD.sub.MD,long/PSD.sub.TD,long2.3, in which PSD.sub.MD,short is an average value of PSD values in a range from 0.15 m to 0.4 m in the longitudinal direction of the surface, PSD.sub.TD,short is an average value of PSD values in a range from 0.15 m to 0.4 m in the lateral direction of the surface, PSD.sub.MD,long is an average value of PSD values in a range from 0.4 m to 5.0 m in the longitudinal direction of the surface, and PSD.sub.TD,long is an average value of PSD values in a range from 0.4 m to 5.0 m in the lateral direction of the surface.

A method, according to one approach, includes forming an underlayer of a magnetic recording medium. The underlayer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an aromatic polymer, and a polymeric binder binding the encapsulated nanoparticles. The underlayer is cured by irradiating the underlayer for causing crosslinking of the polymeric binder. In another approach, a method includes forming an underlayer of a magnetic recording medium by spray coating a mixture of a magnetic nanoparticles, aromatic polymer, and polymeric binder onto a structure as a sprayed-on aerosol coating; and curing the underlayer.

A non-metallic media substrate includes a disc-shaped substrate body having at least one media storage surface on a face thereof. The substrate body has a center opening having an inner diameter and an outer diameter surface, and the substrate body has a thickness. The substrate further includes an annular groove at the outer diameter of the media substrate, the annular groove having chamfered edges and an internal concavity extending toward the inner diameter.