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Millikelvin magnetic relaxation measurements of alpha-Fe2O3 antiferromagnetic particles

E. del Barco·J. M. Hernandez·M. Duran·J. Tejada·R. D. Zysler·M. Vasquez Mansilla·D. Fiorani
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Abstract

In this paper we report magnetic relaxation data for antiferromagnetic alpha-Fe2O3 particles of 5 nm mean diameter in the temperature range 0.1 K to 25 K. The average spin value of these particles S=124 and the uniaxial anisotropy constant D=1.6x10^-2 K have been estimated from the experimental values of the blocking temperature and anisotropy field. The observed plateau in the magnetic viscosity from 3 K down to 100 mK agrees with the occurrence of spin tunneling from the ground state Sz = S. However, the scaling M vs Tln(nu t) is broken below 5 K, suggesting the occurrence of tunneling from excited states below this temperature.

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E. del Barco, J. M. Hernandez, M. Duran, J. Tejada, R. D. Zysler, M. Vasquez Mansilla, D. Fiorani. 2001-04-20. Millikelvin magnetic relaxation measurements of alpha-Fe2O3 antiferromagnetic particles. https://doi.org/10.1103/physrevb.65.052404

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