Comparing effect of electric and magnetic dipoles on their fields

Question

So at the end of one of my prof's lectures he gives us something to think about:

Both electric and magnetic dipoles tend to line up with their respective fields.

Materials made out of electric dipoles cause the electric field that turns the dipoles to be reduced.

Materials made out of magnetic dipoles cause the magnetic field that turns the dipoles to be increased.

Why are the two types of dipoles different in this regard?

Now, this isn't a homework assignment or anything. It is just something to ponder on. I'm curious why this happens.

Answer 1

I don't think this is true. Both electric and magnetic dipoles try to turn against the field around, so the both try to decrease the field.

For example, if we gather many of compasses in one room, they will tend to compensate Earth magnetism.

Meanwhile, there are many sorts of magnetism in materials, some of them try to decrease the field, some try to increase or do something else and all depends on complex microscopic structure of a material nobody understands. ..

Answer 2

This has much to do with convention :

When we talk of electric dipole its potential energy in an electric field is given as $U = -p.E$ here $p$ is dipole moment and $E$ is applied electric field. And when we talk of potential energy of magnet in magnetic field it is given as $U = -m.B$ here $m$ is magnetic moment and $B$ is applied magnetic field.

As you can see from above direction when angle between dipole and field is zero, potential energy is minimum in both cases.

Now let's see the conventions :
1. An electric field goes from positive towards negative while electric dipole is defined to be from negative to positive. 2. A magnetic field goes from north pole to south pole outside magnet and south to north inside, and a magentic moment is also defined to go from north to south outside of its body and south to north inside of its body.

Clearly if we had defined both of the dipoles to be just as the same we define their fields they would both align with their respective fields one would be in stable equilibrium while other will be in unstable equilibrium. So according to convention we make both of the equilibriums stable and assign the dipole moment on its basis.

It is also notworthy that an electric dipole reduces field along its length only between its 2 ends and increases the field outside of its own length. Where on the other hand, a magnetic dipole increases the magnetic field along its length only within its own body and decreases the field outside of its body.