Magnetic Properties of Oxide Surfaces and Films

This chapter discusses the interesting magnetic propertiesoxide surfacemagnetic properties of low-dimensional oxides, especially transition metal (TM) oxides (Sect. 22.1), which have long been the focus of scientific investigations. In recent years, researchers have taken a particular interest in low-dimensional TM oxide systems, especially ultrathin films (in the nanometer thickness range) that typically develop at surfaces and interfaces. In this respect, interfaces are at the heart of the magnetic phenomena associated with low-dimensional systems containing magnetic oxides. Understanding and mastering the physics of interfaces is therefore crucial if we are to manipulate the magnetic properties of such small-scale systems. Thus, several experimental techniques that allow the chemical compositions and magnetic properties of surfaces and interfaces to be probed have been developed over the last century, some of which are described in Sect. 22.2. We also discuss various physical aspects of interfaces between magnetic transition metal oxides (TMOtransition-metal oxide (TMO)) and other magnetic layers (usually magnetic TMs). Since the ferromagnetic (FMferromagnetic (FM)) elemental metals (Fe, Co, and Ni) react strongly with oxygen, chemical interactions at those O∕M interfaces can influence their magnetic properties. In Sect. 22.3, we consider the use of buffer layers—ultrathin layers of a different oxide or metal incorporated at the O∕M interface—as a strategy for controlling such reactions. Finally, Sect. 22.4 provides an overview of the influence of interface chemistry on the magnetic coupling at O∕M interfaces.