Development Of High Frequency ESR System In Pulsed High Magnetic Field And Its Application In The Research Of Magnetic Materials

Electronic spin resonance(ESR), which is also called electronic paramagnetic resonance(EPR), is an effective method to study materials with unpaired electrons. For many years, ESR experiments are conducted at X band, mainly because the electromagnets used in that time can only produce the fields below 1.5 T. X band ESR have low spectral resolution. To detect subtle spectroscopic details, high-field high-frequency ESR measurements are needed. Based on the platform of the Wuhan National High Magnetic Field Center, we developed the high-field high-frequency ESR experiment system using Lab VIEW. The experimental results demonstrated that the ESR experiment system can work successfully and efficiently. The thesis mainly contains following contents:In chapter 1, the background of developing high-field high-frequency ESR is overviewed.In chapter 2, we described the base structure of pulsed high magnetic field.In chapter 3, an ESR facility was developed based on the pulsed high magnetic field.Measurement methods of ESR spectrum and temperature were developed.In chapter 4, we introduced the characteristic of Virtual Instrument(VI), showed how instruments can be controlled with computer.In chapter 5, we designed the software used in the system based on Lab VIEW, which made the system work more efficiently.In chapter 6, we tested the ESR experiment system with sample of Ba3 Mn Sb2O9 and Ca3 Zn Mn O6.This ESR experiment system can achieve a frequency range of 60-520 GHz,temperature down to 2 K and magnetic fields up to 30 T. It uses software to do temperature control and data processing. It works efficiently in ESR measurement.