Structure/property relationships of active sites in disordered (amorphous/nanodomain) materials and single crystals

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Magnetic properties of materials of significant interest in biology, medicine, and industry will be studied by multi-frequency continuous-wave (CW) and pulsed electron magnetic resonance (EMR) techniques, using paramagnetic centres as probes at active sites in these materials. The EMR technique is based on the same principle as that of MRI (Magetic resonance imaging) technique used in hospitals.   1. Multifrequency CW EMR of active sites.   The CW EMR measurements will be carried out in the temperature interval -271 C to +25 C at microwave frequencies in the 9.0 to 350 GHz range. We will measure: 1A. single crystals of rare-earth silicon oxides Y2SiO5 and La2Si2O7  doped with paramagentic ions; 1B. Amorphous materials:(i) Nanodomains: a) Dilute magnetic semiconductors (DMS).  These are oxide materials doped by cobalt and iron ions; b) Ceramics. (ii) Metalloproteins contining doubly ionized iron and triply ionized manganese ions, of importance in biology and medicine.   2. Pulsed EMR. Theoretical calculations will be carried out, taking into account the dipolar interaction between two nitroxide probes that depends on their distance, of signals for: 2A. 2D-ELDOR (two-dimensional electron-electron double resonance); 2B. DQC (double quantum coherence) and DEER (double electron-electron resonance).     The significances of the proposed research are: (1) The "single-crystals"  will  be developed as lasers, phosphors, and materials to be used as replacement  for silicon dioxide gate dielectrics. (2) The DMS samples have the potential to be developed as (spintronic) mass storage devices in hard disks of computers. (3) Novel insights into metalloproteins of interest in biology and medicine will be acquired by developing a better understanding of the properties of exchange-coupled iron centres in these proteins. (4) The pulsed EMR simulations would be used  for distance measurements in biological systems, a topic on the cutting edge of research, providing clues to blueprints in life in the human genome project.