Refrigerator magnets with four poles apiece

[Hornbein]

I bought a couple of bar magnets at the local hardware store. They were acting so strangely. I couldn't figure out where the poles were. Finally I realized each magnet had four poles! They weren't quadropolar, rather half of each bar was magnetized one way and the other half the other way. The field is oriented towards the thnnest dimension of the bar, not the longest like in all of the diagrams. Pretty clever setup.

I suppose that a permanent magnet could have any number of poles greater than 1.

 

[PietKuip]

The Hallbach array, magnetic only on one side:
https://commons.wikimedia.org/wiki/File:Fridge_Magnet_Halbach.svg

 

[Hornbein]

The Hallbach array, magnetic only on one side:
https://commons.wikimedia.org/wiki/File:Fridge_Magnet_Halbach.svg

Nope, these magnets are two-sided and the fields symmetrical.

 

[mathman]

I bought a couple of bar magnets at the local hardware store. They were acting so strangely. I couldn't figure out where the poles were. Finally I realized each magnet had four poles! They weren't quadropolar, rather half of each bar was magnetized one way and the other half the other way. The field is oriented towards the thnnest dimension of the bar, not the longest like in all of the diagrams. Pretty clever setup.

I suppose that a permanent magnet could have any number of poles greater than 1.

Poles come in pairs.

 

[Hornbein]

Poles come in pairs.

https://www.physicsforums.com/threads/three-poled-bar-magnet.786637/

 

[mathman]

https://www.physicsforums.com/threads/three-poled-bar-magnet.786637/

It looked to me like two bar magnets welded together at the south poles.

 

[davenn]

https://www.physicsforums.com/threads/three-poled-bar-magnet.786637/

there's more than 3 poles in the image in that link

 

[Hornbein]

there's more than 3 poles in the image in that link

It depends on how a magnetic pole is defined.

 

[davenn]

It depends on how a magnetic pole is defined.

no, look at the field lines in the image
I can see 4 distinct poles with an unknown area in the middle

 

[Charles Link]

I recently experimented with two flat refrigerator "strip" magnets each about 1" diameter and placed their backs against each other. By orientating them just right I could maximize the adhesion. A little experimentation by sliding one of them across showed that the poles came in strips about 1/8" wide from top to bottom so that they would slide easily in the vertical direction but when sliding horizontal they would click into place after every 1/8" -1/4" of motion. A subsequent google confirmed they are manufactured in such a fashion.