Extreme Field Sensitivity of Magnetic Tunneling in Fe-Doped Li3N

M. Fix, J. H. Atkinson, P. C. Canfield, E. del Barco, A. Jesche
2018 Physical Review Letters  
The magnetic properties of dilute Li_2(Li_1-xFe_x)N with x ∼ 0.001 are dominated by the spin of single, isolated Fe atoms. Below T = 10 K the spin-relaxation times become temperature-independent indicating a crossover from thermal excitations to the quantum tunneling regime. We report on a strong increase of the spin-flip probability in transverse magnetic fields that proves the resonant character of this tunneling process. Longitudinal fields, on the other hand, lift the ground-state
more » ... and destroy the tunneling condition. An increase of the relaxation time by four orders of magnitude in applied fields of only a few milliTesla reveals exceptionally sharp tunneling resonances. Li_2(Li_1-xFe_x)N represents a comparatively simple and clean model system that opens the possibility to study quantum tunneling of the magnetization at liquid helium temperatures.
doi:10.1103/physrevlett.120.147202 pmid:29694147 fatcat:hh6ggzqjnbfnlabbu27jxahaeq