Unusually large magnetic moment and tricritical behavior of the CMR compound NaCr2O4 revealed with high resolution neutron diffraction and μ + SR
Journal article, 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

neutron diffraction

unconventional magnetism

muon spin rotation

colossal magnetoresistance

Author

E. Nocerino

AlbaNova University Center

Ola Kenji Forslund

Chalmers, Physics, Materials Physics

Hiroya Sakurai

National Institute for Materials Science (NIMS)

Akinori Hoshikawa

Ibaraki University

Nami Matsubara

AlbaNova University Center

Daniel Andreica

Babeș-Bolyai University

Anton Zubayer

Linköping University

F. Mazza

Vienna University of Technology

Takashi Saito

High Energy Accelerator Research Organization

Jun Sugiyama

Japan Atomic Energy Agency

Comprehensive Research Organization for Science and Society

I. Umegaki

High Energy Accelerator Research Organization

Yasmine Sassa

Chalmers, Physics, Materials Physics

Martin Månsson

AlbaNova University Center

JPhys Materials

2515-7639 (eISSN)

Vol. 6 3 035009

Realization of Novel Low‐Dimensional Skyrmion Systems

Swedish Research Council (VR) (2017-05078), 2019-06-01 -- 2021-12-31.

Areas of Advance

Materials Science

Subject Categories

Condensed Matter Physics

DOI

10.1088/2515-7639/acdf21

More information

Latest update

7/30/2023