Low-temperature Synthesis and Characterizations of LaFeAsO Nanocrystals

doi:10.15541/jim20150218

Abstract

Abstract:

LaFeAsO as a parent compound of iron-based superconductor was synthesized at low temperatures. The mixtures of La₂O₃, LaCl₃ and BaFe₂As₂ were ball-milled and the pressed pellets were sintered at 500℃ in vacuum. And nanocrystals of LaFeAsO were formed during the solid-state reaction. The solid-state reaction temperature for preparing LaFeAsO is 200℃ lower than the literature reported. The average crystallite size of the as-prepared LaFeAsO is less than 100 nm, as estimated by the X-ray diffraction Scherrer formula. Meanwhile, the c axis of the unit cell is increased by 0.001 nm, primarily stemming from the nanosize effect. Electrical resistivity measurement shows that the spin-density-wave anomaly becomes unremarkable, accompanied by a significant decrease in the transition temperature. The phenomena are discussed in terms of crystallite-size effect and the influence of lattice parameters.

Key words: LaFeAsO, low-temperature solid-state reaction, nanocrystals, spin-density wave

CLC Number:

O614

ZHANG De-Xing, SUN Yun-Lei, ABULIMIT Abuduweli, CAO Guang-Han. Low-temperature Synthesis and Characterizations of LaFeAsO Nanocrystals[J]. Journal of Inorganic Materials, 2015, 30(12): 1273-1277.

Figures/Tables 5

Fig. 1 XRD patterns of the samples in different stages of the low-temperature solid-state reaction for synthesizing LaFeAsO. From bottom to top: (a) mixtures of La2O3, LaCl3 and BaFe2As2; (b) the mixture after ball milling for 6 h; (c) the pellet sintered at 500℃ for 50 h; (d) the pellet re-sintered at 600℃ for 50 h. As a comparison, the XRD pattern of LaFeAsO polycrystals, prepared by a soild-state reaction at 1100℃, is also presented on the top

Table 1 Lattice parameters at room temperature and the crystalline-grain sizes for the as-prepared LaFeAsO nanocrystals and polycrystals

Fig. 2 SEM image (a) of the LaFeAsO sample sintered at 600℃ and typical EDX spectrum (b) for the small particles. The bright large-sized particles are insulating byproduct BaCl2. The dark small-sized particles (~200 nm) are conducting LaFeAsO

Fig. 3 Temperature dependence of resistivity for the LaFeAsO samples sintered at 500℃, 600℃ and 1100℃. The vertical axis of the lower plot adopts the derivative dρ/dT, in which the data are displaced downward for clarity

Fig. 4 Temperature dependence of magnetic susceptibility for the LaFeAsO samples sintered at 500℃ right axis and 1100℃ leftaxis, respectively. The sample by solid-state reaction at 500℃ basically shows a Curie-Weiss paramagnetic behavior, yet it deviates from the Curie-Weiss fit (represented by the solid line) below 50 K

References 11

[1]	QUEBE P, TERBUCHTE L J, JEITSCHKO W.Quaternary rare earth transition metal arsenide oxides RTAsO (T = Fe, Ru, Co) with ZrCuSiAs type structure.J. Alloys Compd., 2000, 302(1): 70-74.
[2]	PEARSON R G.Hard and soft acids and bases.J. Am. Chem. Soc., 1963, 85(22): 3533-3539.
[3]	JIANG H, SUN Y L, XU Z A, CAO G H.Crystal chemistry and structural design of iron-based superconductors.Chin. Phys. B, 2013, 22(8): 087410.
[4]	KAMIHARA Y, WATANABE T, HIRANO M, et al, Iron-based layered superconductor LaO1-xFxFeAs (x = 0.05-0.12) with Tc= 26 K.J. Am. Chem. Soc., 2008, 130(11): 3296-3297.
[5]	DE LA CRUZ C, HUANG Q, LYNN J W, et al. Magnetic order close to superconductivity in the iron-based layered LaO1-xFxFeAs systems.Nature, 2008, 453(7197): 899-902.
[6]	JOHNSTON D C.The puzzle of high temperature superconductivity in layered iron pnictides and chalcogenides.Adv. Phys., 2010, 59(6): 803-1061.
[7]	WANG C, XU Z A, CAO G H.Superconductivity induced by chemical doping in iron-based compounds.Progress in Physics, 2010, 30(3): 307-333.
[8]	FNAG A H, HUANG F Q, XIE X M, et al.Low-temperature rapid synthesis and superconductivity of Fe-based oxypnictide superconductors.J. Am. Chem. Soc., 2010, 132(10): 3260-3261.
[9]	FRANKOVSKY R, MARCHUK A, POBEL R, et al.Synthesis of LaO1-xFxFeAs via solid state metathesis reaction.Solid State Commun., 2012, 152(8): 632-634.
[10]	LEE J Y, ZHANG Q, SAITO F.Mechanochemical synthesis of LaOX (X = Cl, Br) and their soild state solution.J. Solid State Chem., 2001, 160(2): 469-473.
[11]	JIANG S, XING H, XUAN G, et al. Superconductivity up to 30 K in the vicinity of the quantum critical point in BaFe2(As1-xPx)2.J. Phys.: Condens. Matter, 21(38): 382203.

[1]	FAN Jiashun, XIA Donglin, LIU Baoshun. Temperature Dependent Transient Photoconductive Response of CsPbBr₃ NCs [J]. Journal of Inorganic Materials, 2023, 38(8): 893-900.
[2]	ZHANG Guoqing, QIN Peng, HUANG Fuqiang. Reversible Conversion between Space-confined Lead Ions and Perovskite Nanocrystals for Confidential Information Storage [J]. Journal of Inorganic Materials, 2022, 37(4): 445-451.
[3]	LI Tie, LI Yue, WANG Yingyi, ZHANG Ting. Preparation and Catalytic Properties of Graphene-Bismuth Ferrite Nanocrystal Nanocomposite [J]. Journal of Inorganic Materials, 2021, 36(7): 725-732.
[4]	YANG Dandan, LI Xiaoming, MENG Cuifang, CHEN Jiaxin, ZENG Haibo. Research Progress on the Stability of CsPbX₃ Nanocrystals [J]. Journal of Inorganic Materials, 2020, 35(10): 1088-1098.
[5]	DENG Li-Er, LI Yan, GONG Lei, WANG Jia. Preparation of Ag₂S Nanocrystals for NIR Photothermal Therapy Application [J]. Journal of Inorganic Materials, 2018, 33(8): 825-831.
[6]	ZHAO Hai-Bing, XU Hai-Feng, YANG Ke-Wei, LIN Chen-Xue, FENG Miao, YU Yan. Enhanced Photoreversible Color Switching of Methylene Blue Catalyzed by Magnesium-doped TiO₂ Nanocrystals [J]. Journal of Inorganic Materials, 2018, 33(10): 1124-1130.
[7]	ZHU Yun-Rong, CHEN Yu-Yun, XU Guo-Hua, YE Xiao-Jian, ZHONG Jian, HE Dan-Nong. Effect of Silk Fibroin Content on the Bionic Mineralization and In Vitro Cellular Compatibility of Silk Fibroin/Hydroxyapaptite Nanocomposites [J]. Journal of Inorganic Materials, 2012, 27(8): 883-886.
[8]	YANG Xin-Yu, XIANG Wei-Dong, ZHANG Xi-Yan, LIU Hai-Tao, ZHAO Hai-Jun, LIANG Xiao-Juan. Study on the Third-order Optical Nonlinear Absorption Properties of Bi₂O₃ Nanocrystals Glass [J]. Journal of Inorganic Materials, 2012, 27(3): 317-322.
[9]	JIANG Wen-Jun,FANG Jin,FAN Zhong-Yong,YANG Xu-Jie,LU Qi-Ting,HOU Yi-Bin. Synthesis of Nano-sized Tabular Lindgrenite (Cu₃(MoO₄)₂(OH)₂) by Aqueous Precipitation [J]. Journal of Inorganic Materials, 2011, 26(4): 438-442.
[10]	YANG Xin-Yu, , XIANG Wei-Dong, , ZHAO Hai-Jun,ZHANG Xi-Yan, LIANG Xiao-Juan, LIU Hai-Tao. Third-order Nonlinear Optical Properties of Bi₂S₃ Nanocrystals Embedded inSodium Borosilicate Glass [J]. Journal of Inorganic Materials, 2011, 26(3): 290-294.
[11]	SHEN Long-Hai,CUI Qi-Liang. Synthesis of Cubic Chromium Nitride Nanocrystals Powders by Arc Discharge Plasma Method [J]. Journal of Inorganic Materials, 2010, 25(4): 411-414.
[12]	CAI Ke,WANG Hong-Zhe,SHEN Huai-Bin,TAO Xiao-Jun,LI Lin-Song,DU Zu-Liang. Preparation and Optical Properties of CdS∶Cu/CdS Nanocrystals [J]. Journal of Inorganic Materials, 2009, 24(2): 247-250.
[13]	ZHAO Yin,LI Chun-Zhong,LIU Xiu-Hong. Photosensitized Degradation Activity of Dye by Fe-doped TiO₂ Nanocrystals Synthesize via Gas Combustion Flames [J]. Journal of Inorganic Materials, 2007, 22(6): 1070-1074.
[14]	KONG Xiang-Rong,CAI Jun,HU Zhen-Xing,ZENG Yan-Wei. Glycothermal Preparation of Barium Strontium Titanate Nanocrystals [J]. Journal of Inorganic Materials, 2007, 22(5): 833-837.
[15]	YUE Ming-Xin,LI Dian-Chao,YU Li-Xin,WANG Yan. Luminescent Characteristics of ZrO₂ and ZrO₂:Dy³⁺ Nanocrystals [J]. Journal of Inorganic Materials, 2005, 20(5): 1032-1036.