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Figure 7: Calculated orientation distribution of the easy axes of CoFe2O4 nanoparticles in (a) thermal equilibrium at , and (b)–(d) nonequilibrium steady states under AC magnetic field at various and  MHz.The inset shows the dynamic hysteresis loops. Diagrams of the magnetic torques in the AC field are depicted in (e) and (f), where the ellipsoid in each figure shows a nanoparticle, and the broken line, open and closed arrows indicate the directions of the easy axis, magnetic moment of the particle, and the AC magnetic field, respectively. The nonequilibrium structures under the high-frequency AC magnetic field are illustrated in the sketches in the lower column.