Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr2 O4 revealed with high resolution neutron diffraction and μ + SR
Artikel i vetenskaplig tidskrift, 2023
The mixed valence Cr3+/Cr4+ compound NaCr2O4, hosts a plethora of unconventional electronic properties. In the present study, muon spin rotation/relaxation ( μ + SR) and high-resolution time-of-flight neutron powder diffraction measurements were carried out on high-quality samples to clarify the complex magnetic ground state of this unique material. We identified a commensurate canted antiferromagnetic order (C-AFM) with a canting angle of the Cr spin axial vector equal to θ c = ( 8.8 ± 0.5 ) ∘ , and an estimated Cr moment μ C r C ∼ ( 4.30 ± 0.01 ) μ B . Such an unusually large value of μ C r C is compatible with the existence of high-spin Cr sites created by the presence of an unconventional negative charge transfer state in NaCr2O4. In addition to the C-AFM structure, a novel magnetic supercell was also revealed. Such supercell display an incommensurate (IC)-AFM propagation vector (0 0 1 2 − δ ), having a Cr moment μ C r I C = ( 2.20 ± 0.03 ) μ B . It is suggested that the C-AFM and IC-AFM modulations have two different electronic origins, being due to itinerant and localized contributions to the magnetic moment respectively. Finally, the direct measurement of the magnetic order parameter for the C-AFM structure provided a value of the critical exponent β = 0.245 ≈ 1 4 , suggesting a non conventional critical behavior for the magnetic phase transition in NaCr2O4
muon spin rotation
neutron diffraction
colossal magnetoresistance
unconventional magnetism
Författare
E. Nocerino
Alba Nova Universitetscentrum
Ola Kenji Forslund
Chalmers, Fysik, Materialfysik
Hiroya Sakurai
National Institute for Materials Science (NIMS)
Akinori Hoshikawa
Ibaraki University
Nami Matsubara
Alba Nova Universitetscentrum
Daniel Andreica
Universitatea Babes-Bolyai
Anton Zubayer
Linköpings universitet
F. Mazza
Technische Universität Wien
Takashi Saito
High Energy Accelerator Research Organization
Jun Sugiyama
Comprehensive Research Organization for Science and Society (CROSS)
Japan Atomic Energy Agency
I. Umegaki
High Energy Accelerator Research Organization
Yasmine Sassa
Chalmers, Fysik, Materialfysik
Martin Månsson
Alba Nova Universitetscentrum
JPhys Materials
2515-7639 (eISSN)
Vol. 6 3 035009Framtidens Lågdimensionella Skyrmion Material
Vetenskapsrådet (VR) (2017-05078), 2019-06-01 -- 2021-12-31.
Styrkeområden
Materialvetenskap
Ämneskategorier (SSIF 2011)
Den kondenserade materiens fysik
DOI
10.1088/2515-7639/acdf21