I’m flattered you like the concept of Allomancy so much that you want to use it in your work, but it’s best if you come up with your own magic system to write about. Any novel or movie that uses Allomancy would be considered a derivative work, and copyright law assigns all rights to derivative works to the original creator. If you anticipate distribution (direct or indirect) of your project to anyone outside of a very small group of close friends or acquaintances, it’s best for you to come up with your own original concepts.
