|Ph.D Student||Leviant Tom|
|Subject||Energy Bursts from the Fe8 Molecular Magnet during Quantum|
Tunneling of Magnetization Process
|Department||Department of Physics||Supervisor||Professor Amit Keren|
|Full Thesis text|
Single molecule magnets (SMM) have been widely investigated as model compounds for quantum tunneling of magnetization. In the Fe8 molecular magnet tunneling can occur from a meta-stable state to an excited state followed by a transition to the ground state. This transition is accompanied by an energy release of 115.6 GHz. Previous work done by Oren Shafir and Amit Keren showed a jump in the temperature of a thermometer placed far from the sample, every time a tunneling event took place. The first objective of this research was to measure whether this energy is released in the form of thermal or electromagnetic energy. Contrary to a previous publication we find no evidence for the release of electromagnetic radiation. However, under some conditions this release of heat causes magnetization reversal in the form of a deflagration. The deflagration ignites by tunneling and its front velocity is of the order of 1 m/sec. This velocity is sensitive to field gradients and sweep rates. In addition, the propagation velocity of a heat pulse through the sample was measured. These measurements are discussed in the context of deflagration theory.