Spin dynamics of Dy₂ molecules deposited onto micro-SQUID sensors

We report the results of ac susceptibility measurements performed down to very low temperatures (T > 13 mK) on thin layers of asymmetric Dy₂ molecular coordination complexes that have been proposed as candidates for the realization of 2-qubit quantum gates. The molecules are integrated into a μ-SQUID susceptometer by means of Dip Pen Nanolithography. Frequency-dependent susceptibility data measured on 5 and 20 molecular layers thick films are compared with similar results obtained for bulk polycrystalline samples. The results show that the magnetic anisotropy, exchange interactions and spin tunneling rates of Dy₂ units largely remain intact at the surface. Low-nuclearity lanthanide magnetic clusters might then provide suitable building blocks for the development of a scalable hybrid quantum architecture.