Magnetic Properties of Materials

Notes

Diamagnetism and paramagnetism

Diamagnetism is a property of all materials and opposes applied magnetic fields, but is very weak. Paramagnetism, when present, is stronger than diamagnetism and produces magnetization in the direction of the applied field, and proportional to the applied field.Whenever two electrons are paired together in an orbital, or their total spin is 0, they are diamagnetic electrons. Atoms with all diamagnetic electrons are called diamagnetic atoms. A paramagnetic electron is an unpaired electron.

hard magnetic material and magnetic storage

Hard Ferromagnetic. Hard magnets, also referred to as permanent magnets, are magnetic materials that retain their magnetism after being magnetised. Practically, this means materials that have an intrinsic coercivity of greater than \(\sim10kAm^{-1}\).Magnetic storage or magnetic recording is the storage of data on a magnetised medium. Magnetic storage uses different patterns of magnetisation in a magnetisable material to store data and is a form of non-volatile memory. The information is accessed using one or more read/write heads.

Ferrimagnetism and soft magnetic materials

a ferrimagnetic material is one that has populations of atoms with opposing magnetic moments, as in antiferromagnetism; however, in ferrimagnetic materials, the opposing moments are unequal and a spontaneous magnetization remains.This happens when the populations consist of different materials or ions.