Magnetic properties and local microstructures in Zn-doped YMnO{sub 3}
The hole doping effect on the magnetic properties of multiferroic YMn{sub 1−x}Zn{sub x}O{sub 3} was studied through investigating the local microstructures. Polycrystalline YMn{sub 1−x}Zn{sub x}O{sub 3} samples with x ranging from 0 to 0.22 are synthesized by solid-state reaction method. The x-ray diffraction patterns reveal that YMn{sub 1−x}Zn{sub x}O{sub 3} samples with low Zn{sup 2+} doping concentration (x < 0.1) maintain single phase which show hexagonal structure with space group of P6{sub 3}cm. The temperature dependence of magnetization presents that the magnetic moment at low temperature and the FM transition temperature increase with increasing the doping concentration of Zn{sup 2+}. Meanwhile, ferromagnetism induced by Zn{sup 2+} doping is found to become stronger. EXAFS analysis reveals the in-plane Mn-O{sub P} bond length decreases while the out-of-plane Mn-O{sub A} bond length keeps almost constant. The weak FM order is ascribed to order-to-disorder effect resulting from the diluted exchange interaction among Mn{sup 3+} ions and double-exchange interaction between the mixed valence-state of Mn{sup 3+} and Mn{sup 4+} by hole doping of Zn{sup 2+}.