The Mage Winds books from Mercedes Lackey had displaced bubbles of land with assorted creatures, both magical and non, being carried along for the ride.
Just in case someone wants to read the books sometime:The cause was eventually found to be a very powerful magical cataclysm that happened in the region’s past—about 1,000 years before the events in the book—that ruptured space and time. The bubbles of land were determined to be nodes where waves from one magical “explosion” and the other in a different location destructively interfered with each other. The detective work figuring this out is a major sub-plot, with the main plot being coping with the side effects. People disappearing, odd creatures causing problems for locals, earthquakes, fires, an invasion from a neighboring land both blaming Valdemar for the phenomenon and using the chaos as an opportunity to attack, and a body-stealing mage from the time of the Cataclysm for seasoning.
Sheri S. Tepper had the books of the Great Game where psi powers (in the guise of magic) were fueled by pulling the heat out of the surrounding environment. The various abilities of Gamesmen were ranked and codified according to the size of their demesne (area they pulled energy from) and the overall effectiveness of their power. Enormous furnaces were used as sources of mobile concentrated energy for warfare, and one ability was storing energy for later use. They’d sometimes find creatures or powerless people (pawns) who had frozen to death when most of the heat was pulled out of an area by a powerful Gamesman exercising his or her ability.
The most important thing for you with your story is to decide on a set of rules, and stick to them. One of your rules, that where magick works science doesn’t, and vice versa, is pretty good. That’s original, as far as I know. Go with that. Maybe postulate from quantum mechanics that the presence of one kind of energy use collapses the local probability wave function into one set of physical laws or another (or similar technobabble). Set limits on the sphere of influence and in what is possible with magick vs. technology. Limitations are useful for creating tension and avoiding the “pull it out of your ass as you go along” school of plotting (otherwise known as the “reverse the polarity and run it through the deflector dish while clearing the transporter buffer at warp speed” approach to storytelling when related to SF.)
You might toy with the idea of trying to increase local energy use in one form or another to swing the balance the other way. I.e. get a bunch of magick users together and channel energy in a place where magick works, and then move into an area while holding onto that energy where there’s a power plant or something to try and shut the power plant down so that less-powerful mages can work magick there later. A powerful battery or capacitor could be a personal anti-magick device. A simple electric fence with enough voltage could be enough to deter a moderately powerful magickal creature or mage from getting into an area due to the magickal interference.
Work out how much magickal or faerie creatures need magick in their environment. Do unicorns, etc. sicken and die if they are in technological demesnes? Do mages rely on their magick to correct eyesight or other physical defects, or to enhance physical abilities? What happens when they can’t do that? What about the flip side? Do normals find that they’re able to unconsciously or instinctively perform magick when they’re in a magical demesne? Does magickal energy or its effects carry over into a tech bubble? If you transmogrify a person in one place, for example, does he turn back from a frog into a computer geek when he gets close to functioning power lines? If you throw a fireball, does it dissipate when it reaches the edge of the mage’s sphere of influence, or is it disrupted by tech interference?
Whatever you do, don’t include too much explanation in the actual story unless you want to make figuring out this stuff part of the plot. It’s a very good idea to work it out in your head, make an outline and notes on what’s possible and not given your system, but keep it mostly in the background. It’s for you to know and your readers to infer. Don’t explain things much, or even at all. Let most details come out as part of the environment.