Design och konstruktion av mätuppställning för induktiv mätning av magnetisk spinndynamik

• Main Author: Törnman, Ville
• Format: Others
• Language: Swedish
• Published: Uppsala universitet, Fasta tillståndets fysik 2010
• Subjects: magnetisk spinndynamik; Kittel; Gilbert
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122249

Development in spin dynamic occurs in the whole world because of therising demands on fast electronic storage for example hard drivesand RAM (Random Access Memory). Measuring the spin resonance of amaterial gives you the insight of the theoretical speed for amagnetic memory. This means the maximum storage speed is below thefirst resonance. All magnetic materials have different propertiesthat will inflict the resonance frequency which brings that theconstructors of memories need to know which magnetic material theywill use to obtain best results. In the market for normal users themaximum storage speed in a RAM memory is 1.6 GHz. But the memoriesdoes not have magnetic properties because they are made oftransistors. The disadvantages in transistors is that they lose alldata when the power is off. The target of  the diploma thesis is toconstruct the first experiential setup for spin dynamics in Swedenconsisting of a network analyser, waveguide, microwave probes andadjustable magnetic DC-field. The thesis work also included a tripto Germany for measuring on a similar material to achieve someverification on the quality off the measurement setup. Themeasurement setup measure the transmission losses that occur atferromagnetic resonance which are detected by the Network Analyser,the losses are comparable with the susceptibly in themagnetic material which could be derived from the magnetic precisionby Landau-Lifshitz- Gilbert (LLG) equation. The thesis contains somepractical elements like constructing a waveguide by opticallithography, constructing a Helmholtz coil to change the resonancefrequency in the material according to Kittels equation and also amagnetic setup to saturate the rf-field to receive the backgrounddistortion in the measurement for elimination in the spin dynamicmeasurement. Time schedule for the thesis is 20 weeks and the thelocation are at Uppsala University at the institution of solid statephysics.