I was doing and expieriment with Neodymium magnets, (witch can hold up to 5,000 their own weight) and when i heated one to 260C in my oven, when it came out and cooled one pole was stronger then the other. when I put another magnet close to it, i felt the normal same-pole repulsion, just reduced. but when they got within 2 cm of each other, they attracted each other!
My conclusion was the North pole on the heated magnet, which i had observed earlier as stronger than the south pole, attracted the other magnet's south pole and overcame it's weaker side. ive heard that it is impossible for a magnet to be stronger on one side, so do you have any idea how this could have happened?