Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespre...Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespread attention.While altermagnetism has been extensively studied,research on unconventional compensated magnetism remains very rare.In particular,unconventional compensated magnetic materials are only theoretically predicted and have not yet been synthesized experimentally.In this study,based on symmetry analysis and frst-principles electronic structure calculations,we predict that LaMn_(2)SbO_(6)is an unconventional compensated magnetic semiconductor.Given that the Mn ions at opposite spin lattice cannot be connected by any symmetry,the spin splitting in LaMn_(2)SbO_(6)is isotropic.More importantly,LaMn_(2)SbO_(6)has already been synthesized experimentally,and its magnetic structure has been confrmed by neutron scattering experiments.Therefore,LaMn_(2)SbO_(6)serves as an excellent material platform for investigating the novel physical properties of unconventional compensated magnetic materials.展开更多
采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及...采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及老化性能测试等手段,确定了材料粉体最佳煅烧温度,表征了陶瓷体物相、形貌、元素含量、电学性能、稳定性与Al2O3含量的关系。结果表明:(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列热敏陶瓷材料电阻率随着Al2O3含量增加显著增大,但材料常数B值增加平缓。当x=0.15时,该陶瓷材料呈现出低B(2816.44 K)、高阻(11893.89?·cm)的优良电学特性。热敏电阻经125℃老化500 h,阻值漂移(ΔR/R)均小于0.94%。展开更多
A series of pre-reduced LaMn1–xCuxO3 (0≤x<1) catalysts for methanol synthesis from CO2 hydrogenation were prepared by a sol-gel method. The catalytic performances were strongly dependent on the copper content. XR...A series of pre-reduced LaMn1–xCuxO3 (0≤x<1) catalysts for methanol synthesis from CO2 hydrogenation were prepared by a sol-gel method. The catalytic performances were strongly dependent on the copper content. XRD investigation revealed that the single perovskite structure could be preserved after being reduced, when the substitution for Mn by Cu was less than 50%. The Cu-doped (x=0.5) LaMnO3 was much more active than the other catalysts for reaction, showing CO2 conversion up to 11.33% and methanol sele...展开更多
Stoichiometric LaMnO3 and LaCoO3 nanoparticles were synthesized via calcination of a dried solution, containing molar ratio of La（NO3）3＋6H20/[Mn（NO3）2-4H20 or Co（NO3）2-6H20]=1 and citric acid as disperser at te...Stoichiometric LaMnO3 and LaCoO3 nanoparticles were synthesized via calcination of a dried solution, containing molar ratio of La（NO3）3＋6H20/[Mn（NO3）2-4H20 or Co（NO3）2-6H20]=1 and citric acid as disperser at temperature range of 600-900 ℃for 5 h. The role of organic additive concentration, which was 0.0, 1.0, 2.5 and 5 times of the total number of moles of the nitrate ions, was investigated on phase formation, morphology, extent of crystallization and particle size of the products. Products were characterized by X-ray diffraction （XRD）, Fourier-transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM） and Wansmission elec- tron microscopy （TEM） analysis. The tendency of lanthanum ion toward manganese cation was observed to be more than to cobalt cation for the formation of LaBO3 （B： Mn or Co） perovskite phase. A spongy product was formed on perovskite phase formation or in the pres- ence of citric acid. A constructive or destructive effect was observed for the organic disperser on perovskite phase formation, which de- pended on mole of the citric acid.展开更多
采用溶胶-凝胶法制备了钙钛矿型氧化物LaMn 1-x Co xO 3,并以其为光催化剂对模型染料酸性品红进行催化降解实验。研究了Co掺杂量、pH值、染料浓度、催化剂的投加量、以及外加氧化剂H 2O 2投加量等因素对其光催化活性的影响。研究结果表...采用溶胶-凝胶法制备了钙钛矿型氧化物LaMn 1-x Co xO 3,并以其为光催化剂对模型染料酸性品红进行催化降解实验。研究了Co掺杂量、pH值、染料浓度、催化剂的投加量、以及外加氧化剂H 2O 2投加量等因素对其光催化活性的影响。研究结果表明:Co掺杂量x=0.4时,在催化剂投加量0.2 g/L,酸性品红的浓度为10 mg/L,溶液的pH值为7时,酸性品红的降解率可达97%,H 2O 2可提高光催化降解反应的速率。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12204533,12434009,and 62476278)the National Key R&D Program of China(Grant No.2024YFA1408601)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(Grant No.24XNKJ15)。
文摘Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespread attention.While altermagnetism has been extensively studied,research on unconventional compensated magnetism remains very rare.In particular,unconventional compensated magnetic materials are only theoretically predicted and have not yet been synthesized experimentally.In this study,based on symmetry analysis and frst-principles electronic structure calculations,we predict that LaMn_(2)SbO_(6)is an unconventional compensated magnetic semiconductor.Given that the Mn ions at opposite spin lattice cannot be connected by any symmetry,the spin splitting in LaMn_(2)SbO_(6)is isotropic.More importantly,LaMn_(2)SbO_(6)has already been synthesized experimentally,and its magnetic structure has been confrmed by neutron scattering experiments.Therefore,LaMn_(2)SbO_(6)serves as an excellent material platform for investigating the novel physical properties of unconventional compensated magnetic materials.
基金Supported by the National Basic Research Program of China (973 Program,2010CB732300)the National Natural Science Foundation of China (20673037,20601008)the National Key Technologies R&D Program of China (2007BAJ03B01)
文摘采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及老化性能测试等手段,确定了材料粉体最佳煅烧温度,表征了陶瓷体物相、形貌、元素含量、电学性能、稳定性与Al2O3含量的关系。结果表明:(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列热敏陶瓷材料电阻率随着Al2O3含量增加显著增大,但材料常数B值增加平缓。当x=0.15时,该陶瓷材料呈现出低B(2816.44 K)、高阻(11893.89?·cm)的优良电学特性。热敏电阻经125℃老化500 h,阻值漂移(ΔR/R)均小于0.94%。
文摘A series of pre-reduced LaMn1–xCuxO3 (0≤x<1) catalysts for methanol synthesis from CO2 hydrogenation were prepared by a sol-gel method. The catalytic performances were strongly dependent on the copper content. XRD investigation revealed that the single perovskite structure could be preserved after being reduced, when the substitution for Mn by Cu was less than 50%. The Cu-doped (x=0.5) LaMnO3 was much more active than the other catalysts for reaction, showing CO2 conversion up to 11.33% and methanol sele...
文摘Stoichiometric LaMnO3 and LaCoO3 nanoparticles were synthesized via calcination of a dried solution, containing molar ratio of La（NO3）3＋6H20/[Mn（NO3）2-4H20 or Co（NO3）2-6H20]=1 and citric acid as disperser at temperature range of 600-900 ℃for 5 h. The role of organic additive concentration, which was 0.0, 1.0, 2.5 and 5 times of the total number of moles of the nitrate ions, was investigated on phase formation, morphology, extent of crystallization and particle size of the products. Products were characterized by X-ray diffraction （XRD）, Fourier-transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM） and Wansmission elec- tron microscopy （TEM） analysis. The tendency of lanthanum ion toward manganese cation was observed to be more than to cobalt cation for the formation of LaBO3 （B： Mn or Co） perovskite phase. A spongy product was formed on perovskite phase formation or in the pres- ence of citric acid. A constructive or destructive effect was observed for the organic disperser on perovskite phase formation, which de- pended on mole of the citric acid.
