Question

What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player or for building memory stores in a modern computer?

Answer 1

In order to solve this question we need to understand ferromagnetic materials. Actually when any material is not placed in a magnetic field then magnetic dipoles inside the material are randomly oriented, but when these materials are placed in a magnetic medium then dipoles arrange themselves either in parallel or antiparallel manner. Based on order of arrangement, materials are classified as diamagnetic, paramagnetic and ferromagnetic.

Complete answer:
When dipoles arrange themselves antiparallel to the applied field they are known as diamagnetic. Paramagnetic and ferromagnetic are those materials having their dipoles aligned parallel to field direction, but when the magnetic medium is removed then paramagnetic material demagnetizes while ferromagnetic do not, so in this way we can make permanent magnet using ferromagnetic material.

Cassettes or memory used in computers store information in the form of magnetic field, so to store more information they need to store more magnetic field, hence ferromagnetic material proves to be really helpful as it can store large amounts of magnetic field.

Ferrites or ceramic Ferro magnets are used for coating magnetic tapes in a cassette player or for building memory stores in a modern computer. Ferrites consist of compounds like iron, boron or barium, or strontium and molybdenum. They have high magnetic permeability and low hysteresis loss.

Note: It should be remembered that ferromagnetic material has a definite temperature, above which they cease to exhibit spontaneous magnetization called Curie temperature, for example cobalt, iron etc. are ferromagnetic material. Ferro Magnets are considered to be the strongest form of magnetization as they have many unpaired electrons and they align to form macroscopic fields.