Vibrating Sample Magnetometer

• Subject Area: Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: Funded in 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 433501699

The applicant group’s main expertise is in the field of functional nanomaterials with tailored magnetic properties. Here, artificial domain structures and associated microscale magnetic stray field landscapes are investigated for planar layer systems, which are used for manipulation and remote control of magnetic microobjects. Likewise, magnetic properties of magnetically functionalized 3D objects are explored, e.g., magnetic Janus particles and tubular architectures. For this purpose, a profound understanding of the interplay between anisotropies and exchange interaction in magnetic thin films is essential. Here, a central question is how magnetic anisotropies can be tailored by keV helium ion bombardment when combined with external magnetic fields. The focus is on investigating thermally activated processes with respective theoretical modeling and their impact on characteristics of the material systems’ magnetization curves.An essential part for carrying out the currently running and planned projects is a quantitative characterization of the samples’ magnetization curves with high sensitivity to buried layers, curved surfaces and particulate objects. Therefore, an instrument is required, which is capable to characterize the magnetization reversal under systematic variation of the external magnetic field’s direction with respect to the samples’ anisotropy axes, the measurement time and temperature. As investigations on thin magnetic layers in planar, curved and particulate systems are required, an essential condition is to quantify the samples’ magnetic moment with high sensitivity. The described requirements can be entirely fulfilled by a high-performance vibrating sample magnetometer. Because the measurement procedure integrates over the whole sample, this technique is also sensitive to buried layers and is therefore complementary to the Kerr magnetometers and Kerr microscope available in the group. Due to the outdated technology of the group’s home-built vibrating sample magnetometer’s components, its sensitivity is orders of magnitude too low for an adequate sample characterization. In addition, there is no possibility for temperature control and for acquiring angular dependent magnetization curve studies. Therefore, this set-up is not suitable for carrying out the planned investigations. Consequently, the requested new device is necessary for the planned research.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Vibrationsmagnetometer
• Instrumentation Group: 0150 Geräte zur Messung der magnetischen Materialeigenschaften
• Applicant Institution: Universität Kassel
• Leader: Professor Dr. Arno Ehresmann