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Resonant quantum tunneling of spin chains in a three-dimensionnal magnetically ordered state

E. Lhotel·E. N. Khatsko·C. Paulsen
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Abstract

We show that resonant quantum tunneling of the magnetization, until now observed only in zero-dimensional (0D) cluster systems, occurs in the molecular Ising spin chain $[(CH_3)_3NH]CoCl_3\cdot 2H_2O$, which orders as a canted 3D-antiferromagnet at $T_C=4.15 K$. We present three features that prove unambigously the existence of resonant quantum tunneling below $0.3 K$ ($T_C/12$): Temperature independent relaxation of the magnetization, speeding up of the relaxation at a well defined field ($1025 Oe$) and increase of the magnetization each time this field is crossed during a succession of minor hysteresis loops. A mechanism is proposed to describe the behavior based on a simple model of 0D domain wall nucleation.

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E. Lhotel, E. N. Khatsko, C. Paulsen. 2006-08-30. Resonant quantum tunneling of spin chains in a three-dimensionnal magnetically ordered state. https://doi.org/10.1103/physrevb.74.020402

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