Structural and Multiferroic Properties of Self Doped Yttrium Manganites YMn_(1+x)O_3

摘要

We have prepared the polycrystalline samples of compositions YMn_(1+x)O_3 (x =0, 0.17) and studied their structural properties using x-ray diffraction and Raman spectroscopy measurements. The sample with composition Y:Mn = 1:1 showed the antiferromagnetic transition in the magnetization verses temperature (M-T) measurements near 70 K similar to standard YMnO_3. But the sample with composition Y:Mn = 1:1.17 showed glass like magnetic transition around 42 K in the M-T measurements. Also, a hysteresis in the isothermal magnetization curve at 2K was observed for the Mn rich sample, while the linear trend of magnetization with magnetic field was noted for the sample with equal Y/Mn ratio at 2K. We understood that the Mn excess in Mn rich sample results in the formation of Mn~(2+) ions and the magnetic exchange among the Mn~(3+)/Mn~(2+) ions is responsible for the observed magnetic behaviour. The room temperature ferroelectric properties of the studied samples were also investigated by measuring P-E loops.