Transformation to Room Temperature Ferromagnetism on Amorphizing Chromite Thin Films
(English)Article in journal (Other academic) Submitted
Transformation to Ferromagnetic order above room temperature is observed on amorphizing otherwise antiferromagnetic chromite [Y(Yb)CrO3] thin films produced by pulsed laser deposition.. To understand the underlying physics of this phenomenon, we have combined advanced spectroscopy techniques and first-principles calculations. The amorphization is found to be accompanied by an insulator-metal transition, which in turn affects the magnetic properties. The ferromagnetism (FM) is then explained by evoking a number of coexisting effects, namely disordering of Cr-O-Cr bond angles, metallization which introduces free carriers and the presence of mixed valence states (Cr3+ in the bulk and Cr4+ on the surface). They favor FM coupling through double and direct exchange interactions. Although we have used YCrO3 as case study, our results are more general and must apply for a wide range of oxide systems.
IdentifiersURN: urn:nbn:se:kth:diva-94882OAI: oai:DiVA.org:kth-94882DiVA: diva2:526314
under review,-only abstract page included. QS 20122012-05-112012-05-112012-05-11Bibliographically approved