Interaction of [Er(HL)(L)]·4CHCl3·H2O Single-Ion Magnet Complexes with Ferromagnetic Microparticles

Abstract

A new method is developed to control the spin relaxation in single-molecular magnets (SMMs) in order to eliminate spin decoherence to the level acceptable for quantum computing at a relaxation frequency of about 102 Hz and a temperature of 2 K. A significant part of the SMMs has rapid magnetic relaxation proceeding through several parallel channels sensitive to the presence of an external magnetic field. Some of the relaxation channels in such materials (also called single-ion magnets (SIMs)) are suppressed using an electromagnet in macroscopic volumes of complexes. This is unacceptable when individual SIM complexes are used as qubits and forces us to look for ways to use a local magnetic field and other types of complex interactions in a specially selected environment, which provides the Zeeman interaction in the absence of an external field. We demonstrate that a composite material made of SIM complexes with Er3+ ions and ferromagnetic microparticles exhibits a remanent magnetization, which is sufficient to decrease the spin relaxation frequency in the volume. In magnitude, this effect competes with the well-known effect of hybridization of the orbitals of a complex during its interaction with a metallic surface. Therefore, the microstructuring of an array of complexes in a ferromagnetic matrix can be used to create local regions with a controlled magnetic relaxation frequency