Year: 2026
Type: article
Abstract: We investigated spin and orbital magnetic moments of a divalent nickelate $${\text{Na}}_{3}{\text{Ni}}_{2}{\text{BiO}}_{6}$$ Na 3 Ni 2 BiO 6 using the Ni L 2,3 -edge x-ray absorption spectroscopy (XAS) measurements with magnetic circular dichroism (MCD) as well as linear dichroism (LD). In spite of the angular momentum L = 0 ionic ground state of Ni 2+ (t 2g 6 e g 2 ; 3 A 2 ), the sum-rule estimation on the MCD spectrum surprisingly yields the orbital to spin moment ratio of $${m}_{orb}/{m}_{spin}\approx 0.2$$ m orb / m spin ≈ 0.2 , including the existence of a considerable unquenched orbital magnetic moment $${m}_{orb}$$ m orb at the Ni site. Using the many-body full multiplet cluster model analyses on both the MCD and LD spectra, we successfully determined $${m}_{spin}=1.8\pm 0.1 {\mu }_{\text{B}}$$ m spin = 1.8 ± 0.1 μ B , and $${m}_{orb}=0.35\pm 0.03 {\mu }_{\text{B}}$$ m orb = 0.35 ± 0.03 μ B , which agree well with the saturated moment $${m}_{sat}=2.14 \pm 0.03 {\upmu }_{\text{B}}$$ m sat = 2.14 ± 0.03 μ B determined from the magnetization measurement. We found that the considerable unquenched $${m}_{orb}$$ m orb results from spin–orbit coupling (SOC) mixing the $${\text{L}}_{\text{eff}}=1$$ L eff = 1 excited states of 3 T 2 (t 2g 5 e g 3 ) and 1 T 1 (t 2g 5 e g 3 ) and further increases by ~ 10% with the trigonal distortion.
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,290
OpenAlex ID: W7125420773