Size Effect on LuMn2O5Nanorods

Abstract

LuMn2O5 multiferroic nanorods were fabricated using the hydrothermal method with three sizes of diameters ( $\langle L_{C}\rangle )\times \text {axial}$ lengths of 66(22) $\text {nm}\times 18$ (5) nm, 78(38) $\text {nm}\times 22$ (9) nm, and 91(35) $\text {nm}\times 20$ (7) nm, as determined by the field emission transmission electron microscope and selection area electron diffraction. A small ferrimagnetic (FIM) peak was obtained at 27 K from the nanorods with $\langle L_{C}\rangle = 66$ and 78 nm, and the 91 nm sample exhibited FIM behavior below 43 K. All the samples had a hysteresis loop at 2 K. The fitted $\mu _{\mathrm{ eff}}$ (effect moment), $T_{\mathrm {so}}$ (spin-orbit interaction), and the coercively greatly increased with size to $\langle L_{C}\rangle = 91$ nm. These results reveal that the size importantly affects the magnetic properties between $\langle L_{C}\rangle = 78$ and 91 nm. Raman spectra were obtained at various temperatures to determine the effects of the size on the $\langle L_{C}\rangle = 78$ and 91 nm samples. The red-shift of the $\text{A}_{\mathrm {g}}+\mathrm {B}_{\mathrm {1g}}$ mode increased with temperature only for the 91 nm sample, revealing that the interaction between the Mn–O bonds is more sensitive to temperature in larger LuMn2O5 nanorods.