Characterization

To understand the properties and relate them to theory, which is the basis of improving the devices, they need to be thoroughly characterized. This starts with a broad range of techniques for materials structure characterization including x-rays, spectroscopy and surface science methods such as scanning probe microscopy. This will be used to deduce the key materials parameters and correlate them with the composition and structural properties of the crystals and thin films.

Magnetic characterization will be key to the success of the network and the partners have a huge range of techniques at hand: The key techniques to probe the operation of the devices are variable temperature transport measurements that can be used to characterize the magnetodynamics and switching in cryosystems. Setups with temperatures from room temperature down to 15 mK and with vector fields and fields up to 18T will be used for magnetotransport measurements. These systems are equipped with high frequency contacts for measurements up to 40 GHz to probe the ultimate speed limit for the magnetization manipulation. For high-frequency measurements, the necessary components (microwave source, spectrum analyzer, oscilloscopes, etc.) are available. To image magnetization, magnetic microscopy is used. A novel scanning electron microscope with polarization analysis (Spin-SEM or SEMPA) is available for static imaging down to 10 nm spatial resolution. In addition to imaging the surface magnetization, this technique also allows for the imaging of spin accumulation in non-magnetic materials, since the emitted electrons are spin-analyzed. Fast imaging can be carried out using synchrotron sources and using Free Electron Laser Sources. Two advanced Kerr microscopy setups are also available. This imaging will be employed to measure and understand the switching details of the magnetization as necessary to deduce and understand the torque terms.