It shouldn't require re-writing adjacent tracks or sectors. Heating up a portion of the platter makes it easier to change the bits, but the magnetic field doing

It shouldn't require re-writing adjacent tracks or sectors. Heating up a portion of the platter makes it easier to change the bits, but the magnetic field doing the actual writing is still pretty narrow. If MAMR/HAMR has any significant effect on nearby data, I'd guess it would be similar to DRAM rowhammer: repeated writes (and thermal cycles) to one location may cause nearby locations to have increased error rates, but that's not the same as SMR directly clobbering adjacent tracks.