Orbitial Ordering Transition in Ca2RU)4 Observed with Resonant X-ray Diffraction

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Phys. Rev. Lett.

DOI:https://doi.org/10.1103/PhysRevLett.95.136401· OSTI ID:913932

Zegkinoglouo, I; Stempfer, J; Nelson, C; Hill, P; Chakhalian, J; Bernhard, C; Lang, J; Srajer, G; Fukazawa, H

Resonant x-ray diffraction performed at the {angle}{sub II} and {angle}{sub III} absorption edges of Ru has been used to investigate the magnetic and orbital ordering in Ca{sub 2}RuO{sub 4} single crystals. A large resonant enhancement due to electric dipole 2p{yields}4d transitions is observed at the wave-vector characteristic of antiferromagnetic ordering. Besides the previously known antiferromagnetic phase transition at T{sub N}=110 K, an additional phase transition, between two paramagnetic phases, is observed around 260 K. Based on the polarization and azimuthal angle dependence of the diffraction signal, this transition can be attributed to orbital ordering of the Ru t2g electrons. The propagation vector of the orbital order is inconsistent with some theoretical predictions for the orbital state of Ca{sub 2}RuO{sub 4}.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 913932
• Report Number(s): BNL--78500-2007-JA
• Journal Information: Phys. Rev. Lett., Journal Name: Phys. Rev. Lett. Vol. 95; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ABSORPTION
DIFFRACTION
ELECTRIC DIPOLES
ELECTRONS
MONOCRYSTALS
NSLS
POLARIZATION
VECTORS
X-RAY DIFFRACTION
national synchrotron light source