Origin of multiferroic spiral spin order in the RMnO3 perovskites

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.78.155121· OSTI ID:979251

Dong, Shuai ^[1]; Yu, Rong ^[1]; Yunoki, S. ^[2]; Yunoki, Seiji ^[3]; Liu, J. -M. ^[4]; Dagotto, Elbio R ^[1]

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1. ORNL
2. Istituto Nazionale per la Fisica della Materia and International School, Italy
3. RIKEN, Japan
4. Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing

The origin of the spiral spin order in perovskite multiferroic manganites RMnO3 R=Tb or Dy is here investigated using a two eg-orbital double-exchange model. Our main result is that the experimentally observed spiral phase can be stabilized by introducing a relatively weak next-nearest-neighbor superexchange coupling 10% of the nearest-neighbor superexchange. Moreover, the Jahn-Teller lattice distortion is also shown to be essential to obtain a realistic spiral period. Supporting our conclusions, the generic phase diagram of undoped perovskite manganites is obtained using Monte Carlo simulations, showing phase transitions from the A-type antiferromagnet, to the spiral phase, and finally to the E-type antiferromagnet, with decreasing size of the R ions. These results are qualitatively explained by the enhanced relative intensity of the superexchanges.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 979251
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 15 Vol. 78; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ORIGIN
PEROVSKITE
PEROVSKITES
PHASE DIAGRAMS
SPIN