Magnetic properties of BiMnO3 studied with dc and ac magnetization and specific heat

摘要

Magnetic and specific heat measurements were performed in a single-phased powder BiMnO3 sample prepared at 6 GPa and 1383 K. The imaginary part of the ac susceptibilities showed strong frequency dependence below the ferromagnetic Curie temperature of 98 K. The relaxation measurements revealed time-dependent magnetic properties below 98 K. These data indicate the appearance of a "spin-glass-like" state in BiMnO3. Specific heat measurements showed the existence of ferromagnetic spin waves. However, no simple term C-m proportional to T-3/2 was found indicating an unconventional behavior of the magnetic specific heat. The Debye temperature was estimated to be 410 K using isostructural compounds BiScO3 and BiCrO3.