EDTA-assisted hydrothermal synthesis and magnetic properties of urchin-like YbMn2O5 microspheres

Urchin-like YbMn2O5 microspheres have been fabricated by EDTA (ethylene diamine tetra acetic acid)-assisted hydrothermal method. The results demonstrated that EDTA played key roles in growth of urchin-like YbMn2O5 microspheres. Magnetic measurement indicated that YbMn2O5 showed a weak ferromagnetic at low temperature due to incomplete spin compensation on the surface. The divagation between field cooling and zero field cooling curves could be reasonably ascribed to the collaboration result of spin-glass behavior and the antiferromagnetic (AFM) ordering of the Yb3+ magnetic moments. Exchange bias (a shift in the hysteresis loop toward negative axis) could be observed in both YbMn2O5 microspheres and nanorods (without EDTA). With the increasing particle size, the exchange bias field and the coercivity increased.