We report
the synthesis of the title compounds and the refinement of their structures using Rietveld analysis of powder XRD data. All belong to the monoclinic space group P21/n. While the crystallographic formula can be written as La2(Co)2a(Co1=3M2=3)2bO6 for M= Nb or
Ta, indicating the highest possible order for the cations, we find La2(Co2/3V1/3)2a(Co2/3V1/3)2bO6 for V replacement indicating the highest disorder configuration. The cell volume for La2Co4=3M2=3O6 decreases as the ionic radius of the M5+ cation decreases. These compounds were previously shown to be ferrimagnetic with Curie temperatures in the range 60-70 K. Since the incorporation of cations with the sp hybridized lone pair can potentially induce ferroelectric properties, we also synthesized La4=3Bi2=3Co4=3Ta2=3O6 where we found a partial cations disorder. Crystal and magnetic structures refined with powder
neutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented. neutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented.
Ta, indicating the highest possible order for the cations, we find
La2(Co2/3V1/3)2a(Co2/3V1/3)2bO6 for V replacement indicating the highest disorder configuration. The cell volume for La2Co4=3M2=3O6 decreases as the ionic radius of the M5+ cation decreases. These compounds were previously shown to be ferrimagnetic with Curie temperatures in the range 60-70 K. Since the incorporation of cations with the sp hybridized lone pair can potentially induce ferroelectric properties, we also synthesized La4=3Bi2=3Co4=3Ta2=3O6 where we found a partial cations disorder. Crystal and magnetic structures refined with powder
neutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented.
neutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented.
1/n. While the crystallographic formula can be written as La2(Co)2a(Co1=3M2=3)2bO6 for M= Nb orTa, indicating the highest possible order for the cations, we find
La2(Co2/3V1/3)2a(Co2/3V1/3)2bO6 for V replacement indicating the highest disorder configuration. The cell volume for La2Co4=3M2=3O6 decreases as the ionic radius of the M5+ cation decreases. These compounds were previously shown to be ferrimagnetic with Curie temperatures in the range 60-70 K. Since the incorporation of cations with the sp hybridized lone pair can potentially induce ferroelectric properties, we also synthesized La4=3Bi2=3Co4=3Ta2=3O6 where we found a partial cations disorder. Crystal and magnetic structures refined with powder
neutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented.
neutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented.
2(Co2/3V1/3)2a(Co2/3V1/3)2bO6 for V replacement indicating the highest disorder configuration. The cell volume for La2Co4=3M2=3O6 decreases as the ionic radius of the M5+ cation decreases. These compounds were previously shown to be ferrimagnetic with Curie temperatures in the range 60-70 K. Since the incorporation of cations with the sp hybridized lone pair can potentially induce ferroelectric properties, we also synthesized La4=3Bi2=3Co4=3Ta2=3O6 where we found a partial cations disorder. Crystal and magnetic structures refined with powderneutrons diffraction measurements as well as the infrared spectroscopic characterization, now in progress, will be presented.
