Saturation remanence loops for grain-oriented electrical steel (
Br denotes
remanence and
Hc is the
coercivity). The default definition of magnetic remanence is the magnetization remaining in zero field after a large magnetic field is applied (enough to achieve
saturation). It is called the
initial remanence or the
isothermal remanent magnetization (IRM). Another kind of IRM can be obtained by first giving the magnet a saturation remanence in one direction and then applying and removing a magnetic field in the opposite direction. Yet another kind of remanence can be obtained by demagnetizing the saturation remanence in an ac field. This is called
AC demagnetization remanence or
alternating field demagnetization remanence and is denoted by symbols like
Maf(
H). If the particles are noninteracting single-domain particles with uniaxial
anisotropy, there are simple linear relations between the remanences. and is assumed in some models to represent the lowest-energy state for a given field. There are several ways for experimental measurement of the anhysteretic magnetization curve, based on fluxmeters and DC biased demagnetization. ARM has also been studied because of its similarity to the write process in some magnetic recording technology and to the acquisition of
natural remanent magnetization in rocks. ==Examples==