A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

Embodiments of the invention include an electrical package and methods of forming the package. In one embodiment, a transformer may be formed in the electrical package. The transformer may include a first conductive loop that is formed over a first dielectric layer. A thin dielectric spacer material may be used to separate the first conductive loop from a second conductive loop that is formed in the package. Additional embodiments of the invention include forming a capacitor formed in the electrical package. For example, the capacitor may include a first capacitor plate that is formed over a first dielectric layer. A thin dielectric spacer material may be used to separate the first capacitor plate form a second capacitor plate that is formed in the package. The thin dielectric spacer material in the transformer and capacitor allow for increased coupling factors and capacitance density in electrical components.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate including a polyester as a main component, a base layer disposed on the substrate, a magnetic layer disposed on the base layer, and a back layer disposed on a side of the substrate opposite to the base layer. A surface of the back layer opposite to the substrate has a kurtosis of 2.0 or more. On a surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 10 or more and 200 or less per 1600 μm.sup.2. A surface of the magnetic layer has arithmetic average roughness Ra of 2.5 nm or less. The entire magnetic recording medium has a BET specific surface area of 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate including a polyester as a main component, a base layer disposed on the substrate, a magnetic layer disposed on the base layer, and a back layer disposed on a side of the substrate opposite to the base layer. A surface of the back layer opposite to the substrate has a kurtosis of 2.0 or more. On a surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 10 or more and 200 or less per 1600 μm.sup.2. A surface of the magnetic layer has arithmetic average roughness Ra of 2.5 nm or less. The entire magnetic recording medium has a BET specific surface area of 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. The substrate includes a polyester as a main component. The average thickness of the base layer is 0.9 μm or less. The base layer and the magnetic layer each include a lubricant. The magnetic layer has a surface having a large number of holes, and the arithmetic average roughness Ra of the surface is 2.5 nm or less. The BET specific surface area of the entire magnetic recording medium is 3.5 m.sup.2/g or more in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 90 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. On the surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 20 or more and 200 or less per 1600 μm.sup.2. On the surface of the magnetic layer, a logarithmic decay rate determined by a pendulum viscoelasticity test at a temperature of 10° C. or higher and 45° C. or lower is 0.025 or more and 0.035 or less. A difference between a maximum value of the logarithmic decay rate and a minimum value of the logarithmic decay rate is 0 or more and 0.020 or less. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 80 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.

A magnetic recording medium that can exhibit good traveling performance during use is provided. This magnetic recording medium is a tape-shaped magnetic recording medium, and includes a substrate, a base layer disposed on the substrate, and a magnetic layer disposed on the base layer. On the surface of the magnetic layer, recesses having a depth of 20% or more of the average thickness of the magnetic layer are formed at a ratio of 20 or more and 200 or less per 1600 μm.sup.2. On the surface of the magnetic layer, a logarithmic decay rate determined by a pendulum viscoelasticity test at a temperature of 10° C. or higher and 45° C. or lower is 0.025 or more and 0.035 or less. A difference between a maximum value of the logarithmic decay rate and a minimum value of the logarithmic decay rate is 0 or more and 0.020 or less. The squareness ratio in the perpendicular direction is 65% or more. The average thickness of the magnetic layer is 80 nm or less. The average thickness of the magnetic recording medium is 5.6 μm or less.