Room temperature ferromagnetic‐like response in “bulk” Y‐doped CeO2

Strong ferromagnetic‐like response is observed at room temperature in “bulk”‐ and nano‐crystalline Y‐doped CeO2. The saturation magnetization for “bulk” (∼600 nm) crystallites of CeO2 doped with 25 at.% Y is more than an order of magnitude higher compared to its nanocrystalline (∼10 nm) counterpart. High frequency electron spin resonance and 89Y nuclear magnetic resonance measurements indicate clustering of electronic defects in the “bulk” crystallites. The remarkable size dependence of the magnetic behavior likely originates from a collective magnetic response of defect‐lined nanodomain interfaces in the “bulk” crystallites, consistent with the giant orbital paramagnetism model. Bulk (∼600 nm) crystallites of heavily Y‐doped CeO2 display remarkable ferromagnetic‐like response at room temperature. This response can be linked to the formation of defect‐lined nanodomain interfaces in the interior of heavily doped crystals that result in the appearance of coherent mesoscopic domains with giant orbital paramagnetism.