Structural and magnetic properties of RTiNO{sub 2} (R=Ce, Pr, Nd) perovskite nitride oxides

Journal Article · Sun Mar 15 00:00:00 EDT 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2015.01.023· OSTI ID:22475666

Porter, Spencer H. ^[1]; Huang, Zhenguo ^[1]; Cheng, Zhenxiang ^[1]; Avdeev, Maxim ^[2]; Chen, Zhixin; Dou, Shixue ^[1]

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1. Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong 2522, NSW (Australia)
2. Bragg Institute, Australian Nuclear Science and Technology Organization, Menai 2234, NSW (Australia)

Neutron powder diffraction indicates that CeTiNO{sub 2} and PrTiNO{sub 2} crystallize with orthorhombic Pnma symmetry (Ce: a=5.5580(5), b=7.8369(7), and c=5.5830(4) Å; Pr: a=5.5468(5), b=7.8142(5), and c=5.5514(5) Å) as a result of a{sup –}b{sup +}a{sup –} tilting of the titanium-centered octahedra. Careful examination of the NPD data, confirms the absence of long range anion order in both compounds, while apparent superstructure reflections seen in electron diffraction patterns provide evidence for short range anion order. Inverse magnetic susceptibility plots reveal that the RTiNO{sub 2} (R=Ce, Pr, Nd) compounds are paramagnetic with Weiss constants that vary from −28 to −42 K. Effective magnetic moments for RTiNO{sub 2} (R=Ce, Pr, Nd) are 2.43 μ{sub B}, 3.63 μ{sub B}, and 3.47 μ{sub B}, respectively, in line with values expected for free rare-earth ions. Deviations from Curie–Weiss behavior that occur below 150 K for CeTiNO{sub 2} and below 30 K for NdTiNO{sub 2} are driven by magnetic anisotropy, spin–orbit coupling, and crystal field effects. - Graphical abstract: The structure and magnetism of the oxide nitride perovskites RTiNO{sub 2} (R=Ce, Pr, Nd) have been explored. The average symmetry is shown to be Pnma with a random distribution of oxide and nitride ions and a{sup −}b{sup +}a{sup −} tilting of the titanium-centered octahedra, but electron diffraction shows evidence for short range anion order. All three compounds are paramagnetic but deviations from the Curie Weiss law are seen below 150 K for R=Ce and below 30 K for R=Nd. - Highlights: • The oxide nitride perovskites RTiNO{sub 2} (R=Ce, Pr) have been prepared and their structures determined. • Diffraction measurements indicate short range cis-order of O and N, but no long range order. • Compounds are paramagnetic with Weiss constants that vary from −28 to −42 K. • CeTiO{sub 2}N and NdTiO{sub 2}N deviate from Curie–Weiss behavior below 150 and 30 K, respectively.

• OSTI ID: 22475666
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 226; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANIONS
ANISOTROPY
CERIUM COMPOUNDS
CRYSTAL FIELD
CURIE-WEISS LAW
ELECTRON DIFFRACTION
LATTICE PARAMETERS
MAGNETIC MOMENTS
MAGNETIC SUSCEPTIBILITY
NEODYMIUM COMPOUNDS
NEUTRON DIFFRACTION
ORTHORHOMBIC LATTICES
PARAMAGNETISM
PEROVSKITE
PRASEODYMIUM COMPOUNDS
REFLECTION
SPIN
TITANIUM NITRATES