Slow Magnetic Relaxation of Ni(III) Complexes toward Molecular Spin Qubits.

Molecule‐based magnetic materials are promising candidates for molecular spin qubits, which utilize spin relaxation behavior. Various kinds of transition metal complexes with S=1/2 have been reported to act as spin qubits with long spin‐spin relaxation times (T2). However, the spin qubit properties of low‐spin Ni(III) complexes are not as well known since Ni(III) compounds are often unstable. We report here the slow magnetic relaxation behavior and T2 values for three kinds of low‐spin Ni(III) based complexes with S=1/2 under magnetically diluted conditions. [Ni(cyclam)X2]Y (cyclam=1,4,8,11‐tetraazacyclotetradecane) with octahedral structures and [Ni(mnt)2]− (mnt=maleonitriledithiolate) with a square‐planar structure underwent slow magnetic relaxations in the presence of a dc magnetic bias field. From electron spin resonance (ESR) spectroscopy, the Ni(III) complexes exhibited observable T2, indicating that Ni(III) complexes are promising candidates for use as molecule‐based spin qubits. [ABSTRACT FROM AUTHOR]