1. Magnetism and anomalous apparently inverse Jahn-Teller effect in Sr 2 CrO 4
- Author
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Justin Jeanneau, Pierre Toulemonde, Gyorgy Remenyi, André Sulpice, Claire V. Colin, Vivian Nassif, Emmanuelle Suard, Frederic Gay, Ruben Weht, Manuel Núñez-Regueiro, Magnétisme et Supraconductivité (MagSup ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Matériaux, Rayonnements, Structure (MRS), CRG et Grands Instruments (CRG ), Institut Laue-Langevin (ILL), ILL, Automatisation et Caractérisation (AUTOCARAC ), and Comisión Nacional de Energía Atómica [ARGENTINA] (CNEA)
- Subjects
Physics ,Condensed matter physics ,Magnetism ,Jahn–Teller effect ,Neutron diffraction ,General Physics and Astronomy ,Crystal structure ,01 natural sciences ,010305 fluids & plasmas ,[PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con] ,Condensed Matter::Materials Science ,Tetragonal crystal system ,Octahedron ,Condensed Matter::Superconductivity ,0103 physical sciences ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,[PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el] ,010306 general physics ,Degeneracy (mathematics) ,ComputingMilieux_MISCELLANEOUS - Abstract
We have performed neutron diffraction measurements of tetragonal Sr2 CrO4 to study the crystallographic structure as a function of temperature and the magnetic properties developed below . We have measured the precise positions of the oxygen atoms of the CrO6 octahedra and observed that, with decreasing temperature, the octahedra pass from elongated to almost ideal, contradicting the intuitive idea of a Jahn-Teller effect. DFT calculations explain this apparent anomalous behaviour by establishing that energy level degeneracy only exists in a highly elongated octahedra. Our study agrees with the idea of a weak orbital ordering transition around 150 K followed by an itinerant antiferromagnetic ordering at 110 K with a wave vector determined both from neutron powder diffraction and theory.
- Published
- 2019