Explain the following terms as they are applied to magnetic storage technology.

Question

a. Domain
b. Permeability
c. Magnetostriction
d. Remnant field
e. Ferromagnetic
f. Curie temperature
g. Hard
h. Soft

Answer 1

a. Domain A domain is a region of a magnetic material where the atoms are all magnetized in
the same direction.
b. Permeability Permeability is a measure of the ability of a material to support a magnetic field.
It’s rather like the equivalent of conductivity in the electricity world; a highly
(magnetic) permeable material allows a magnetic flux to pass easily.
c. Magnetostriction Magnetostriction is the ability of a material to change its dimensions under the
influence of a magnetic field. This phenomenon is responsible for the hum you
hear from transformers in power stations. Its inverse effect is that movement
(changing the dimensions of a magnetic material by hitting it) causes a magnetic
field which can be harmful (cause errors) in disk drives etc.
d. Remnant field Remnant magnetization is the field that remains in a magnetic material after any
external field has been removed. The material used to make read/write?heads
should have a very low remnant field.
e. Ferromagnetic Ferromagnetic is a term used to describe a material that can be permanently
magnetized. Although “ferro” implies “iron”, it is possible to build magnets with
materials other than iron.
f. Curie temperature The Curie temperature is the temperature at which a ferromagnetic material loses
its ferromagnetic property; that is, it can no longer retain a magnetic field. The
Curie temperature for iron is about 770°C. Typical rare earth magnets have a Curie
temperature in the region of 310°C. Rare earth magnets are made of metals like
samarium and cobalt, and neodymium, iron and boron.
g. Hard Magnetically hard materials are easy to magnetize permanently.
h. Soft Magnetically soft materials become magnetized under the influence of an external
field, but lose their magnetization when the field is removed.