Magnetic tape device, magnetic reproducing method, and head tracking servo method

A magnetic tape device comprising:

• a magnetic tape;
• and
• a servo head,
• wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,
• the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• the magnetic layer includes a servo pattern,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,
• ΔSFD=SFD25° C.−SFD−190° C. Expression 1
• in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.

A magnetic tape device comprising:

• a magnetic tape;
• and
• a reproducing head,
• wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,
• the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• a ratio Sdc/Sac of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

A magnetic tape device comprising:

• a magnetic tape;
• and
• a servo head,
• wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,
• the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• the magnetic layer includes a servo pattern,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• a ratio Sdc/Sac of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

A magnetic reproducing method comprising:

• reproducing information recorded on a magnetic tape by a reproducing head,
• wherein a magnetic tape transportation speed during the reproducing is equal to or lower than 18 m/sec,
• the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,
• ΔSFD=SFD25° C.−SFD−190° C. Expression 1
• in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.

A magnetic reproducing method comprising:

• reproducing information recorded on a magnetic tape by a reproducing head,
• wherein a magnetic tape transportation speed during the reproducing is equal to or lower than 18 m/sec,
• the reproducing head is a magnetic head including a tunnel magnetoresistance effect type element as a reproducing element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• a ratio Sdc/Sac of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

A head tracking servo method comprising:

• reading a servo pattern of a magnetic layer of a magnetic tape by a servo head in a magnetic tape device,
• wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,
• the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• the magnetic layer includes the servo pattern,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1 is equal to or smaller than 0.50,
• ΔSFD=SFD25° C.−SFD−190° C. Expression 1
• in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.

A head tracking servo method comprising:

• reading a servo pattern of a magnetic layer of a magnetic tape by a servo head in a magnetic tape device,
• wherein a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec,
• the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element,
• the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support,
• the magnetic layer includes the servo pattern,
• a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm,
• the magnetic layer includes one or more components selected from the group consisting of fatty acid and fatty acid amide,
• a C-H derived C concentration calculated from a C-H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %, and
• a ratio Sdc/Sac of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster of the magnetic tape in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.