# A ferromagnet exposed to two fields at the same time?

1. Nov 14, 2013

### Dash-IQ

A piece of iron is placed in exterior magnetic field(+B1,"Going right"), with H = 100 Oe
At the same time, there is another opposite magnetic field acting on that same iron (-B2,"Going Left") with H = 10 Oe

They oppose each other, the iron is magnetized initially by B1, what happens when the second field is introduced while B1 still exists?
Magnetization stays the same? Since the intensity of the first field(B1) is stronger by a factor of 10, however, the coercivity of that iron material is 0.5 Oe, Magnetization = 0?
That's what is confusing me here... And that's the most important thing
For reference:

Last edited: Nov 14, 2013
2. Nov 15, 2013

### mikeph

It wouldn't stay the same unless the magnet is still saturated at 90. The external fields combine additively so just think of it going form 0 to 100 to 90. So you go somewhere up on the BH curve then probably start moving back down, albeit on a higher trajectory.

3. Nov 15, 2013

### Dash-IQ

H1 - H2 = 90 Oe, since they are both vectors, makes sense.
But what does not is the iron core gets magnetized/demagnetized @ 0.5 Oe, if there are values greater than that in both directions, shouldn't magnetization = 0?

4. Nov 16, 2013

### Dash-IQ

By increasing the intensity of the field, the iron ferromagnet becomes a permanent magnet?
Since H is beyond the coercivity.