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Interfacial ferromagnetism in LaNiO3/CaMnO3 superlattices
A J Grutter1, H Yang, B J Kirby
1Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Physical Review Letters
|September 10, 2013
Summary
Interfacial ferromagnetism emerges in superlattices of lanthanum nickelate and calcium manganite. This magnetism is linked to the conducting state of lanthanum nickelate, suggesting a double exchange interaction mechanism.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Magnetism
Background:
- Superlattices composed of paramagnetic LaNiO3 and antiferromagnetic CaMnO3 were investigated.
- LaNiO3 displays a thickness-dependent metal-insulator transition, influencing emergent properties.
Purpose of the Study:
- To investigate interfacial ferromagnetism in LaNiO3/CaMnO3 superlattices.
- To determine the relationship between the electronic state of LaNiO3 and the onset of ferromagnetism.
- To identify the location and mechanism of the observed ferromagnetism.
Main Methods:
- Fabrication of superlattices with varying LaNiO3 layer thicknesses.
- Utilized multiple magnetic probes to characterize magnetic properties.
- Analyzed the correlation between electrical conductivity and magnetic ordering.
Main Results:
- Ferromagnetism was observed only when LaNiO3 layers were in a metallic state.
- The ferromagnetism was localized to a single unit cell of CaMnO3 at the interface.
- The emergence of ferromagnetism coincided with the conducting state of LaNiO3.
Conclusions:
- Interfacial ferromagnetism in these superlattices is strongly dependent on the electronic state of the adjacent metallic layer.
- A double exchange interaction mechanism, mediated by itinerant electrons in LaNiO3, is proposed to explain the ferromagnetism in CaMnO3.
- This study highlights the potential for controlling magnetic properties through interfacial engineering in oxide heterostructures.
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