We study the role of orbital degrees of freedom in perovskite manganites, which are well known as colossal-magnetoresistance (CMR) compounds. The double degeneracy of the (Formula presented) orbitals is treated with isospin. Orbital polarization is essential to explain the variety of phases in these compounds and their physical properties. Especially important is the fact that the orbital is aligned as (Formula presented) in the metallic layered antiferromagnetic state, which explains the experimentally observed quasi-two-dimensional transport and absence of spin canting. A large orbital fluctuation in the ferromagnetic state is also predicted.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1998 Jan 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics