From Superparamagnetism to Macroscopic Quantum Tunneling with Individual Nanostructures of SrRuO3

Abstract:

The interest in magnetization reversal in nanostructures mainly focuses on two phenomena: the superparamagnetic behavior at a temperature range below the Curie temperature and the expected crossover between thermally-activated reversal to reversal dominated by macroscopic quantum tunneling at sufficiently low temperatures. Here we explore both phenomena by monitoring individual reversals in nanostructures of SrRuO3 and obtain novel insight of both phenomena. In particular, we show for the first time the applicability of the Langevin equation to superparamagnetic fluctuations of an individual volume [1] and we find compelling indication for magnetization reversal dominated by macroscopic quantum tunneling below a record high temperature of  10 K [2].

References

1. O. Sinwani, J. W. Reiner, and L. Klein (2014). Monitoring superparamagnetic Langevin behavior of individual SrRuO3nanostructures. Phys. Rev. B 89 020404(R).
2. O. Sinwani, J. W. Reiner, and L. Klein (2012). Indication for macroscopic quantum tunneling below 10 K in nanostructures of SrRuO3. Phys. Rev. B 86 100403(R).