The 3d Mn orbitals in Pr 0.25Ca 0.25MnO 3 (PCMO), in the ferromagnetic phase, were imaged by two-dimensional reconstruction of spin-polarized electron-momentum density projected along the  and  principal directions. The results were analyzed using a molecular-orbital scheme to understand the population distribution for the t 2g and the e g states for Mn. The analysis shows that the t 2g states are found to be half-filled, whereas, the e g states are dominated mainly by x2-z2-type orbitals for both projected  and  principal directions. The observance of preferential filling of the x2-z2-orbital type is consistent with a cooperative Jahn-Teller distortion of the MnO 6 octahedra leading to a local tetragonal compression along the y axis for this system. As a result of this distortion, the 3y2-r2-type orbitals have a small population for PCMO; the ratio of the x2-z2-type orbitals to that of the 3y2-r2-type orbitals is greater than 2, similar to that seen for bilayered manganites.
|Physical Review B - Condensed Matter and Materials Physics
|Published - Jan 25 2012
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics