Fig. 2: µSQUID loops.
a Temperature dependence of the magnetisation curves and b their derivatives for T < 0.1 K, at a fixed sweeping rate of 8 mT/s. The red-dotted lines indicate the relaxation steps present even at the lowest temperature of T ≈ 25 mK, while the black-dotted lines mark the steps that appear as T increases. c The Zeeman diagram obtained by diagonalisation of the Spin Hamiltonian given by Eq. 4 with g = 2, \({B}_{2}^{0}\) = −5.2 × 10−1 GHz, \({B}_{2}^{2}\) = 1.0 × 10−1 GHz and \({B}_{4}^{4}\) = −3.5 × 10−4 GHz.
