Reading the interaction between vortex textures in an FORC diagram

Resumen

Many modern spintronic devices are based on large arrays of magnetic elements, where the interaction between them and their magnetic textures is often a key part of their performance. The experimental characterization of such arrays is challenging because it involves the knowledge of the magnetization process of millions of single elements over areas as large as several square millimeters. When the magnetic textures within the nanoelements interact between them, a characterization over the entire array can be complicated. Here, we show how the interaction between vortex textures in adjacent ferromagnetic dots can be read in a First Order Reversal Curve (FORC) diagram. Using a 9 mm2 array of ferromagnetic nanodots, we show how the shape and position of the prominent features in the FORC diagram (FD) describe the vortex nucleation and annihilation process. The intensity of these peaks gives information on how smooth the mobility of the vortex within the nanodot is. Also, by comparing the intensity of the main features, the FD is particularly sensitive to when the vortices start interacting strongly with neighboring vortices. Micromagnetic simulations and measurements in arrays of different materials confirm our interpretation. With this work, we show the potential of the FD for disentangling the average magnetization process and the complex interactions between the different elements in a large array of nanostructures.