Direct Investigation of Orbital Ordering in a Colossal Magnetoresistance Manganite by Means of X-ray Linear Dichroism at the Mn L Edge

We have investigated for the first time the orbital ordering in a three-dimensional colossal magnetoresistance manganite, namely La7/ 8Sr1/8MnO3, by applying soft X-ray linear dichroism (XLD) to the Mn L edge. We found that the cooperative Jahn−Teller distorted orthorhombic phase, which is present at a temperature of 240 K, is probably accompanied by a predominantly cross type (x 2 − z 2)/(y 2 − z 2) orbital ordering. This result is discussed in the light of different exchange interaction models.