Welcome to PF;
My understanding is that "superparamagnatism" is a grouping of different effects which were discovered separately. It's a bit like asking "who discovered electricity".
Universality in quantum critical flow of charge and heat in ultraclean graphene
https://www.nature.com/articles/s41567-025-02972-z
Some articles indicate that graphene broke a fundamental law. It didn't. It did something unexpected or otherwise, not fully understood.