TY - JOUR
T1 - Antiferromagnetic order of the Co2+ high-spin state with a large orbital angular momentum in La1.5Ca0.5CoO4
AU - Okamoto, Jun
AU - Nakao, Hironori
AU - Yamasaki, Yuichi
AU - Wadati, Hiroki
AU - Tanaka, Arata
AU - Kubota, Masato
AU - Horigane, Kazumasa
AU - Murakami, Youichi
AU - Yamada, Kazuyoshi
PY - 2014/4/15
Y1 - 2014/4/15
N2 - The antiferromagnetic insulator La1.5Ca0.5CoO 4 has been investigated by Co L2,3-edge and O K-edge X-ray absorption spectroscopy (XAS) measurements and Co L2,3-edge resonant soft X-ray magnetic scattering (RXMS) measurement to determine the Co electronic structures associated with magnetic ordering. Co L2,3-edge linear-dichroic XAS shows that Co2+ takes a high-spin (HS) state and Co3+ takes a low-spin (LS) state. Using Co L2,3-edge RXMS, we directly determined that an antiferromagnetic order is formed with a HS state of Co2+ ions. Moreover, the spin and orbital angular momenta of the Co2+ HS state are quantitatively estimated to be 1.1 ± 0.1 and 1.0 ± 0.1, respectively, and to align parallel in the ab plane by utilizing the cluster model calculation. The large orbital angular momentum of the Co2+ HS state originates from the small D4h -symmetry crystal field splitting of t2g levels, which is comparable with the spin-orbit coupling constant of the Co 3d orbital.
AB - The antiferromagnetic insulator La1.5Ca0.5CoO 4 has been investigated by Co L2,3-edge and O K-edge X-ray absorption spectroscopy (XAS) measurements and Co L2,3-edge resonant soft X-ray magnetic scattering (RXMS) measurement to determine the Co electronic structures associated with magnetic ordering. Co L2,3-edge linear-dichroic XAS shows that Co2+ takes a high-spin (HS) state and Co3+ takes a low-spin (LS) state. Using Co L2,3-edge RXMS, we directly determined that an antiferromagnetic order is formed with a HS state of Co2+ ions. Moreover, the spin and orbital angular momenta of the Co2+ HS state are quantitatively estimated to be 1.1 ± 0.1 and 1.0 ± 0.1, respectively, and to align parallel in the ab plane by utilizing the cluster model calculation. The large orbital angular momentum of the Co2+ HS state originates from the small D4h -symmetry crystal field splitting of t2g levels, which is comparable with the spin-orbit coupling constant of the Co 3d orbital.
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U2 - 10.7566/JPSJ.83.044705
DO - 10.7566/JPSJ.83.044705
M3 - Article
AN - SCOPUS:84897542794
VL - 83
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 4
M1 - 044705
ER -