An aluminum alloy disc blank for a magnetic disc made of an aluminum alloy containing Fe: 0.005 to 1.800 mass % with the balance being Al and inevitable impurities, wherein a flatness change of the aluminum alloy disc blank for a magnetic disc when the aluminum alloy disc blank for a magnetic disc is held in the atmosphere at 50° C. or lower for 336 hours is 2.0 μm or less.

An aluminum alloy disc blank for a magnetic disc made of an aluminum alloy containing Fe: 0.005 to 1.800 mass % with the balance being Al and inevitable impurities, wherein a flatness change of the aluminum alloy disc blank for a magnetic disc when the aluminum alloy disc blank for a magnetic disc is held in the atmosphere at 50° C. or lower for 336 hours is 2.0 μm or less.

There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, “%”) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an Al—Fe-based intermetallic compound having a longest diameter of 2 μm or more and less than 3 μm is dispersed at a distribution density of 1000 particles/mm.sup.2 or more, and a Mg—Si-based intermetallic compound having a longest diameter of 1 μm or more is dispersed at a distribution density of 1 particle/mm.sup.2 or less; a method for producing the same; and a magnetic disk in which an electroless Ni—P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, “%”) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an Al—Fe-based intermetallic compound having a longest diameter of 2 μm or more and less than 3 μm is dispersed at a distribution density of 1000 particles/mm.sup.2 or more, and a Mg—Si-based intermetallic compound having a longest diameter of 1 μm or more is dispersed at a distribution density of 1 particle/mm.sup.2 or less; a method for producing the same; and a magnetic disk in which an electroless Ni—P plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

A method includes immersing a wafer in an electrolyte including a plurality of compounds having elements of a high damping magnetic alloy with very low impurity and small uniform grain size. The method also includes applying a pulsed current with a certain range of duty cycle and pulse length to the wafer when the wafer is immersed in an electrolyte. The wafer is removed from the electrolyte when a layer of the high damping magnetic alloy is formed on the wafer.

The present disclosure generally related to read heads having dual free layer (DFL) sensors. The read head has a sensor disposed between two shields. The sensor is a DFL sensor and has a surface at the media facing surface (MFS). Behind the DFL sensor, and away from the MFS, is a rear hard bias (RHB) structure. The RHB structure is disposed between the shields as well. In between the DFL sensor and the RHB structure is insulating material. The RHB is disposed on the insulating material. The RHB includes a RHB seed layer as well as a RHB bulk layer. The RHB seed layer has a thickness of between 26 Angstroms and 35 Angstroms. The RHB seed layer ensures the read head has a strong RHB magnetic field that can be uniformly applied.

Provided is an aluminum alloy substrate for a magnetic disk that includes an aluminum alloy containing 0.4 to 3.0 mass % (hereinafter abbreviated as “%”) of Fe, 0.005% to 1.000% of Cu, and 0.005% to 1.000% of Zn, with a balance of Al and unavoidable impurities. This substrate has a ratio A/B of 0.70 or more, where A indicates a distribution density of Al—Fe intermetallic compound particles having maximum diameters of 10 μm or more and less than 16 μm, and B indicates a distribution density of Al—Fe intermetallic compound particles having maximum diameters of 10 μm or more. The distribution density of Al—Fe intermetallic compound particles having maximum diameters of 40 μm or more is at most one per square millimeter. Also provided are a method of fabricating this aluminum alloy substrate for a magnetic disk and a magnetic disk composed of the aluminum alloy substrate for a magnetic disk.

Provided is an aluminum alloy substrate for a magnetic disk that includes an aluminum alloy containing 0.4 to 3.0 mass % (hereinafter abbreviated as “%”) of Fe, 0.005% to 1.000% of Cu, and 0.005% to 1.000% of Zn, with a balance of Al and unavoidable impurities. This substrate has a ratio A/B of 0.70 or more, where A indicates a distribution density of Al—Fe intermetallic compound particles having maximum diameters of 10 μm or more and less than 16 μm, and B indicates a distribution density of Al—Fe intermetallic compound particles having maximum diameters of 10 μm or more. The distribution density of Al—Fe intermetallic compound particles having maximum diameters of 40 μm or more is at most one per square millimeter. Also provided are a method of fabricating this aluminum alloy substrate for a magnetic disk and a magnetic disk composed of the aluminum alloy substrate for a magnetic disk.

There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, %) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an AlFe-based intermetallic compound having a longest diameter of 2 m or more and less than 3 m is dispersed at a distribution density of 1000 particles/mm.sup.2 or more, and a MgSi-based intermetallic compound having a longest diameter of 1 m or more is dispersed at a distribution density of 1 particle/mm.sup.2 or less; a method for producing the same; and a magnetic disk in which an electroless NiP plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.

There are provided: an aluminum alloy substrate for a magnetic disk, the aluminum alloy substrate including an aluminum alloy including 0.4 to 3.0 mass % (hereinafter, %) of Fe, less than 0.10% of Si, less than 0.10% of Mg, and the balance of Al and unavoidable impurities, in which an AlFe-based intermetallic compound having a longest diameter of 2 m or more and less than 3 m is dispersed at a distribution density of 1000 particles/mm.sup.2 or more, and a MgSi-based intermetallic compound having a longest diameter of 1 m or more is dispersed at a distribution density of 1 particle/mm.sup.2 or less; a method for producing the same; and a magnetic disk in which an electroless NiP plating treatment layer and a magnetic layer thereon are disposed on a surface of the aluminum alloy substrate for a magnetic disk.