# Units for susceptibility Xm

1. Sep 17, 2005

### sniffer

i think magnetic susceptibility xm=M/H is contant and independent of the units we are working with.

in different refferences, they sometimes quote mks or cgs units which gives different value of Xm. It confuses me. Is Xm units dependent?

for example Xm for oxygen is about 10^-4 in cgs units but 10^-8n in mks units. i get very confused. :yuck:

2. Sep 18, 2005

### inha

The values mean the same. They just differ by constants. Convert the value from one unit system to another and you'll see that.

3. Sep 19, 2005

### shyboy

You are not the first, neither you will be the last. The problem is that magnetization and magnetic field may be measured in different units. The relation between magnetization, magnetic field strength, and magnetic field is also different in SI and Gauss system. Moreover, there are two versions of gauss system for electromagnetic units!

Gauss system
Electromagnetic
$$B=H+4\pi M$$
Electrostatic
$$c^2 B=H+4\pi M$$

SI

$$B=\mu_0 (H+M)$$

4. Sep 19, 2005

### Gokul43201

Staff Emeritus
You're hardly alone.

The cgs unit is emu/cc-Oe, the SI unit is A/m-T. The conversion factor, however, should only be $4 \pi$.

Can you provide your source ?