The magnetic tape device includes a TMR head (servo head); and a magnetic tape, in which a magnetic layer of the magnetic tape includes fatty acid ester, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 7.0 nm, a difference between spacings before and after the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm, and SFD (=SFD.sub.25 C.SFD.sub.190 C.) in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50.

A PWM modulation circuit controls low-side transistors of three phases to all be in an ON state when a brake current flows; controls, in a period in which a brake current flows in a first direction in one phase, a transistor for sensing in that one phase to be in an ON state; and controls, in a period in which a brake current flows in the first direction in two phases, transistors for three phases to be in an OFF state. When the brake current is to flow, sense-phase control circuits for the three phases control a transistor for sensing, in a phase in which the brake current flows in a sink direction, to be into an ON state, and controls the transistor for sensing in a phase in which the brake current flows in an opposite direction, to be into an OFF state.

Embodiments of the present invention provide a tape transport control system with enhanced regulation of tape tension and velocity over the entire length of the tape. The tape transport control system comprises of circuitry adapted to output and circuitry adapted to receive one or more signals representing a tape velocity, at least one radius of either the first tape reel or the second tape reel, and a tape tension, and based on the received signals, generate at least one control signal to control at least one of the first reel motor or the second reel motor so as to reduce a tension disturbance at a minimum, one frequency corresponding to a time-varying reel-rotation frequency, based on controller parameters that depend on the tape velocity and on the at least one radius of either the first tape reel or the second tape reel.

In one general embodiment, a method includes forming a first magnetic layer, forming a tunnel barrier layer above the first magnetic layer, and forming a second magnetic layer above the tunnel barrier layer. The tunnel barrier layer includes crystalline alumina. The tunnel barrier layer is formed at a temperature of less than 100 degrees centigrade.

In one general embodiment, a method includes forming a first magnetic layer, forming a tunnel barrier layer above the first magnetic layer, and forming a second magnetic layer above the tunnel barrier layer. The tunnel barrier layer includes crystalline alumina. The tunnel barrier layer is formed at a temperature of less than 100 degrees centigrade.

A PWM modulation circuit controls low-side transistors of three phases (u, v, and w) all to be into an ON state, when a brake current flows, controls, in a period in which a brake current flows in one phase, a transistor for sensing (u, v, and w) of this one phase to be into an ON state, and controls, in a period of two phases, the transistor for sensing (u, v, and w) of three phases to be into an OFF state. When the brake current is to flow, sense-phase control circuits of three phases controls a transistor for sensing (u, v, and w), in a phase in which the brake current is in a sink direction, to be into an ON state, and controls the transistor for sensing (u, v, and w) in a phase in which it is in an opposite direction, to be into an OFF state.

The magnetic tape device includes a TMR head and a magnetic tape, in which the magnetic tape includes fatty acid ester in a magnetic layer, Ra measured regarding a surface of the magnetic layer is 2.0 nm or smaller, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and 7.0 nm or smaller, a difference between spacings before and after the vacuum heating is greater than 0 nm and 8.0 nm or smaller, and a ratio 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 thereof in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.

Embodiments of the present invention provide a tape transport control system with enhanced regulation of tape tension and velocity over the entire length of the tape. The tape transport control system comprises of circuitry adapted to output and circuitry adapted to receive one or more signals representing a tape velocity, at least one radius of either the first tape reel or the second tape reel, and a tape tension, and based on the received signals, generate at least one control signal to control at least one of the first reel motor or the second reel motor so as to reduce a tension disturbance at a minimum, one frequency corresponding to a time-varying reel-rotation frequency, based on controller parameters that depend on the tape velocity and on the at least one radius of either the first tape reel or the second tape reel.

Provided is a magnetic tape device in which a magnetic tape transportation speed is equal to or lower than 18 m/sec, Ra measured regarding a surface of a magnetic layer of a magnetic tape is equal to or smaller than 2.0 nm, 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 SFD (=SFD.sub.25 C.SFD.sub.190 C.) in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50, with the SFD.sub.25 C. being SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25 C., and the SFD.sub.190 C. being SFD measured at a temperature of 190 C.

An apparatus, according to one embodiment, includes: a module; and a plurality of tunnel valve read transducers arranged in an array extending along the module. Each of the tunnel valve read transducers includes: a sensor structure having a tunnel barrier layer and a free layer. Moreover, each of the tunnel valve read transducers includes a pair of hard bias magnets which sandwich the respective sensor structure therebetween, the hard bias magnets being positioned on opposite sides of the sensor structure along a cross-track direction. Furthermore, a thickness of each of the hard bias magnets at a thickest portion thereof is at least 10 times greater than a thickness of the free layer. Other systems, methods, and computer program products are described in additional embodiments.