Within the realm of high-entropy materials, high-entropy oxides have triggered a lot of interest since the first report by Rost et al. in 2015. High entropy oxides are composed of at least 5+ cations (crystal structure dependant) randomly and homogeneously distributed within a well-defined crystal lattice. Resulting intrinsic elemental, charge and spin disorders/distortions do not only lead to phase stabilization (i.e., high-entropy stabilization) but also to so-called cocktail effects and sluggish diffusion. Consequently, high-entropy materials expand the parametric space available to tune physical and chemical properties beyond the current state of the art in many fields and applications, such as fundamental research disordered systems, and more specifically, spin glass, spin liquid, and superconductivity.
 
Due to electron disorder, the cation outer shell electron configurations differ between high-entropy oxides and their low-entropy counterparts, causing the appearance of new charge and spin states. Accompanying crystal lattice disorders, in return, may lead to lattice vibration changes (i.e., phonon state) compared to their parent low-entropy compounds. Consequently, re-distribution of outer shell electrons as well as abnormal phonon-electron and phonon-phonon interactions will occur, significantly changing the elemental states of all components as well as the band states within the crystal. This should lead to significant changes in transport and magnetization phenomena in high entropy oxides that may pave the way towards technological breakthroughs in the future, especially since high-entropy material systems have a wide compositional flexibility to adjust the properties to research or application-specific needs.
 
In a series of perovskite-based B-site high-entropy oxides, a disorder magnetization state with strong spin interaction, occurring jointly with a gradual phase transition process, has been observed. By combing this result with transport (electrical and thermal) measurements, we would like, herein presented, to discuss connections between these physical behaviors and the intrinsic disorder in high-entropy oxides. This study will highlight their potential benefits for various technological applications and more specifically sensors, thermoresistance as well as thermoelectricity.