G. de Loubens et al 2008 EPL 83 37006 doi:10.1209/0295-5075/83/37006
G. de Loubens1, D. A. Garanin2, C. C. Beedle3, D. N. Hendrickson3 and A. D. Kent1
Show affiliationsSpin relaxation between the two lowest-lying spin-states has been studied in the S=4 single-molecule magnet Ni4 under steady-state conditions of low amplitude and continuous microwave irradiation. The relaxation rate was determined as a function of temperature at two frequencies, 10 and 27.8 GHz, by simultaneously measuring the magnetization and the absorbed microwave power. A strong temperature dependence is observed below 1.5 K, which is not consistent with a direct single-spin-phonon relaxation process. The data instead suggest that the spin relaxation is dominated by a phonon bottleneck at low temperatures and occurs by an Orbach mechanism involving excited spin-levels at higher temperatures. Experimental results are compared with detailed calculations of the relaxation rate using the universal density matrix equation.
Issue 3 (August 2008)
Received 22 April 2008, accepted for publication 16 June 2008
Published 18 July 2008
G. de Loubens et al 2008 EPL 83 37006
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