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 [(CH3)3NH]CoCl3⋅2H2O, which orders as a canted 3D-antiferromagnet at TC=4.15K. We present three features that prove unambigously the existence of resonant quantum tunneling below 0.3K (TC/12): Temperature independent relaxation of the magnetization, speeding up of the relaxation at a well defined field (1025Oe) 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.
@article{arxiv.cond-mat/0512052,
title = {Resonant quantum tunneling of spin chains in a three-dimensionnal magnetically ordered state},
author = {E. Lhotel and E. N. Khatsko and C. Paulsen},
journal= {arXiv preprint arXiv:cond-mat/0512052},
year = {2007}
}