The emergence of a ferromagnetic component in ${\text{LaMnO}}_3$ with low Cr-for-Mn substitution has been studied by x-ray absorption spectroscopy and x-ray magnetic circular dichroism at the Mn and Cr $K$ edges. The local magnetic moment strengths for Mn and Cr are proportional to each other and follow the macroscopic magnetization. The net ferromagnetic components of ${\text{Cr}}^{3+}$ and ${\text{Mn}}^{3+}$ are found antiferromagnetically coupled. Unlike hole doping by La site substitution, the inclusion of ${\text{Cr}}^{3+}$ ions up to $x=0.15$ does not decrease the Jahn-Teller (JT) distortion and consequently does not significantly affect the orbital ordering. This demonstrates that the emergence of the ferromagnetism is not related to JT weakening and likely arises from a complex orbital mixing.

• Received 1 February 2013

DOI:https://doi.org/10.1103/PhysRevB.87.220404