Research

Our main line of scientific investigation involves the study of various magnetic materials through the analysis of their macroscopic and local properties over a wide range of temperatures and applied magnetic fields. Among the specific research areas in which we have worked are frustrated magnetism, Bose-Einstein condensation of magnons, and magnetism in molecular, organic, and organometallic systems.

Magnetic frustration is an exciting and diverse research area in condensed matter physics. Its origin is related to the incompatibility between magnetic interactions and the geometry of crystal lattices based on triangles and tetrahedra, resulting in new states of matter related to quantum fluctuations and different topological constraints. One of the main reasons for the interest in these systems is the fact that geometric frustration causes large quantum spin fluctuations at extremely low temperatures, leading to the emergence of interesting new types of quantum magnetic ground states with no classical analogs. Geometrically frustrated magnetic materials have been the subject of study by Prof. Freitas for the past fifteen years. These studies have been very successful, resulting in the publication of highly impactful papers. Among them, there is the article on "artificial spin ices" that was chosen for the cover of the prestigious journal Nature, which has had a significant impact in the field (with over 500 citations to date), marking a new paradigm for the study of magnetic frustration, where topology related to frustration is no longer the fortuitous result of the combination of elements in crystalline oxides but rather the conscious outcome of designing the particular structure of interest. Other highly influential works in the field involve the study of residual entropy in "spin ices", resulting in an article published in the journal Nature Physics and another in the journal Physical Review Letters. In the area of organic magnetic systems, a notable work highlighted the existence and control of magnetic order in purely organic compounds of the radicals F4BImNN and BImNN, a paper published in the Journal of the American Chemical Society.