Unveiling the shape-selective CoCr2-yScyO4 nanomagnetism

In this study CoCr2-yScyO4 (y = 0, 0.01, 0.02, and 0.03) nanoparticles (NPs) have been synthesized following the solution combustion method and characterized by combining experimental techniques with high-throughput Density Functional Theory calculations. The structural analysis confirmed the crystalline nature with spinel cubic structure exhibiting an average particle size between 7 and 10 nm. The morphological analysis confirmed the exposure of the (220), (311), (400), and (422) planes in agreement with theoretical results based on Wulff Construction. Magnetic analysis indicated the existence of paramagnetic to ferrimagnetic phase transition at the critical temperature (Tc) and a conical spiral spin phase was found at the spiral transition temperature (Ts). In both the cases, the transition temperature was seen to decrease with increase in the Sc content in agreement with the exchange-coupling constants calculated by DFT, where a singular magneto-structural behavior was observed. Theoretical results for shape-oriented magnetic properties indicate the anisotropic spin density distribution and surface exposure, providing a general picture of shape-selective control of nanomagnetism.