Synthesis, structure, and magnetic behavior of nanoparticles of cubic ZnMnO3.

Synthesis and nature of magnetism in ZnMnO3 nanoparticles with cubic spinel structure (a = 8.369 Å and size D ≃ 25 nm) are reported. Magnetization M vs. H and M vs. T data yield ferrimagnetism with TN ≃ 20 K, μ/Mn = 4.46 μB, MS ≃ 18.5 emu/g, and a transition at TS ≃ 7 K. For T < TN, coercivity and exchange-bias approach zero at TN with anomaly at TS. Using magnetic data and simulations, structure of [Zn2+][1/3]O11/3 with antiparallel moments of Mn4+ and Mn3+ is proposed. [ABSTRACT FROM AUTHOR]