Combustion synthesis,structural,magnetic and dielectric properties of Gd3+-doped lead molybdato-tungstates  

作　　者：T.GRON M.MACIEJKOWICZ E.TOMASZEWIC M.GUZIK M.OBOZ B.SAWICKI S.PAWLUS A.NOWOK Z.KUKULA 

机构地区：[1]Institute of Physics,University of Silesia,40-007 Katowice,Poland [2]Faculty of Chemical Technology and Engineering,Department of Inorganic and Analytical Chemistry,West Pomeranian University of Technology in Szczecin,Al.PiastOw 42,71-065 Szczecin,Poland [3]Faculty of Chemistry,University of Wrocław,ul.F.Joliot-Curie 14,50-383 Wrocław,Poland

出　　处：《Journal of Advanced Ceramics》2020年第2期255-268,共14页先进陶瓷（英文）

基　　金：This work was partly supported by Ministry of Science and Higher Education(Poland)and funded from Science Resources:No.1S-0300–500-1-05-06 and UPB-DZS 518-10-020-3101-01/18;One of us(M.Maciejkowicz)would like to thank for the financial support from National Science Center of Poland for the grant PRELUDIUM 14 No.UMO-2017/27/N/ST8/00741.

摘　　要：Gd^3+-doped lead molybdato–tungstates with the chemical formula of Pb1–3xxGd2x(MoO4)1–3x(WO4)3x(where x=0.0455,0.0839,0.1430,corresponding to 9.53,18.32,33.37 mol%of Gd^3+,respectively,as well asdenotes cationic vacancies)were successfully synthesized via combustion route.The XRD and SEM results confirmed the formation of single-phase,tetragonal scheelite-type materials(space group I41/a)with the uniform,spherical and oval grains ranging from 5 to 20mm.Individual grains are strongly agglomerated into big clusters with the size even above 50mm.The magnetic measurements as well as the Brillouin fitting procedure showed paramagnetic state with characteristic superparamagnetic-like behaviour and the short-range ferromagnetic interactions.The electrical and broadband dielectric spectroscopy studies revealed insulating properties with the residual electrical n-type conduction of 2×10^–9 S/m and low energy loss(tand»0.01)below 300 K.Dielectric analysis showed that no dipole relaxation processes in the Gd^3+-doped materials were observed.A fit of dielectric loss spectra of Gd^3+-doped samples by sum of the conductivity and the Havriliak–Negami,Cole–Cole,and Cole–Davidson functions confirmed this effect.

关 键 词：SCHEELITE Gd^3+-substituted PbMoO4 combustion solid solution magnetic properties dielectric properties 

分 类 号：TB34[一般工业技术—材料科学与工程]