Tunnelling secrets extracted
Article Abstract:
Molecular chemistry and low-temperature physics of manganese acetate provides evidence of resonant tunnelling between magnetization states. Analysis of the phonon-assisted transitions shows the magnetic macromolecule acting as a giant spin at low temperatures, and supports the notion of both phonons and nuclear spins playing an important role in the quantum relaxation of insulating nanomagnets. The nuclear spins force the system to resort to resonant tunnelling, and the results have important implications for nanomolecular engineering of magnetic memory elements.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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Experimental evidence for non-exponential decay in quantum tunnelling
Article Abstract:
It is possible to use a quantum tunnelling experiment to produce evidence of short-time deviation from exponential decay. Ultra-cold sodium atoms are trapped in an accelerating periodic optical potential formed by a standing wave of light, and can escape the wells by quantum tunnelling. Over short periods, the survival probability is at first constant. Over longer periods, the characteristics of exponential decay emerge. Further research will look at the possibility of suppressing tunnelling by repeated measurements during the non-exponential period.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Macroscopic quantum tunnelling of magnetization in a single crystal of nanomagnets
Article Abstract:
A crystal composed of super-paramagnetic manganese clusters (Mn(sub 12)-ac), at low temperature, demonstrates tunnelling between quantum mechanical behavior at the microscopic level and classical behavior at the macroscopic level. The magnetization exhibits hysteresis loops with staircase structure indicating quantization of the magnetization. The magnetic relaxation of the Mn(sub 12)-ac crystal is enhanced when the spin-up and spin-down level scheme coincide indicating the existence of resonant macroscopic quantum tunnelling in the magnetic system.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
User Contributions:
Comment about this article or add new information about this topic:
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