| Nederlands

Multiferroic perovskites under epitaxial strain : the case of TbMnO3 thin films

(2009) Daumont, Christophe Jean Maurice

This dissertation presents the experimental investigation of the structure and physical properties of thin films of the multiferroic TbMnO3 under compressive epitaxial strain. Multiferroic compounds are a class of material exhibiting both spontaneous electrical polarization and magnetization, within the same phase. These materials are rare in nature and efforts are devoted to the discovery/synthesis of new multiferroics. Multiferroics are good candidates to display high magnetoelectric response. This class of materials, in which the electrical and magnetic orders are coupled, has great potential in spintronics or non-volatile 4-state memories. However, the reported couplings are usually too weak to be implemented for applications. Possible ways to enhance the materials’ response, are to use an appropriate dopant, to apply an external pressure or to apply epitaxial strain. While the understanding of the fundamental mechanisms related to the appearance of multiferroicity in some materials has greatly improved over the last few years, many theoreticians and experimentalists are working towards finding new systems with enhanced magneto(-di)electric response, or modifying an existing material in an attempt to enhance the magnetoelectric coupling or to create newmultiferroics.
The scope of this thesis is to study the role of epitaxial strain on a multiferroic material. We focus on one of the most popular multiferroics, TbMnO3, in which the spontaneous electrical polarization is due to a spiral spin ordering, giving rise to a large magnetoelectric coupling. Moreover, large strain effects can be expected in such system because of the subtle balance between the magnetic interactions and its large magnetic frustration. Despite its interest, no reports on TbMnO3 under epitaxial strain were available at the beginning of our study. We have investigated the structure and properties of compressively strained thin films of TbMnO3,with thickness below100nm.

	Titel en inhoudsopgave
	Hoofdstuk 1
	Hoofdstuk 2
	Hoofsdtuk 3
	Hoofdstuk 4
	Hoofdstuk 5
	Hoofdstuk 6
	Engelse samenvatting
	Samenvatting
	Bibliografie
	Publicaties
	Dankwoord
	Stellingen
	Volledige dissertatie