Tables 2-4 list the means and the standard uncertainties of the saturation and remanent moments and the intrinsic coercivity
across the laboratories.
Beacause of the push toward higher coercivity
, two broad categories have been established or magnetic tapes based on this property.
In addition, some tape has dual coercivity
, combining hi-co and lo-co for multifunction cards.
But one is not likely to thoroughly overwrite the data on a high-density diskette, which has a coercivity
of about 700 Oe, because most drive heads cannot come close to the recommended 3,500 Oe.
As DDS media has evolved from the initial MP formulation to the MPI++++ use in DAT 72 media, the magnetic particles have become smaller with higher coercivity
, making a major contribution to the 18x capacity increase over the last decade.
The high coercivity
, high signal to noise ratio and superior frequency characteristics make BaFe magnetic particles a cutting-edge technology that can help further increase the capacity of magnetic tape.
To avoid superparamagnetic effects, disc media manufacturers have been increasing the coercivity
(the "field" required to write a bit) of the media.
For the last 30 years, data storage manufacturers have known that thin metallic high coercivity
films on flexible substrates produce excellent performance in high frequency recording.
Higher Signal to Noise Ratio: Fujifilm scientists identified hexagon-shaped barium-ferrite magnetic particles as having the smaller size, higher coercivity
and low noise needed to produce the high signal-to-noise ratio required for high density recording media; and
supply PVC cards personalized high coercivity
magnetic stripe and ID-1 format for issuing the EHIC.
Media approaches include a longer length of thinner substrate tape or wider tape and high coercivity
, while drive changes can include higher linear bit density, data compression, advanced encoding, and track positioning servo.
This latter intercomparison will be limited to NdFeB, because, in this configuration, the high remanence and low coercivity
of AlNiCo8 make it difficult to correct for demagnetizing effects.