Physico-Chemical nanomaterials science
Slowed magnetic relaxation in the Er3+ single ion magnet in the absence of external magnetic field 
O.Koplak1, E.Dvoretskaya2, E.I. Kunitsyna2, T.A. Bazhenova2, E.B. Yagubskii2, A.Calloni1, F.Goto1, G.Bussetti1, R.Morgunov2
1 Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano
o.koplak@gmail.com

2Institute of Problems of Chemical Physics, 142432 Chernogolovka, Russia

Single-molecule magnets (SMMs) attract great interest of specialists in the view of development of platforms for quantum computation and information storage [1, 2]. Typical SMM involves a magnetic ion incorporated in organic structure chemically designed to satisfy desirable symmetry of the ligand field. More or less strong coupling between an ionic spin and organic environment is provided due to spin-orbital interaction within the complex. The Er3+ based complexes demonstrate relaxation typical for single ionic magnets (SIMs). Magnetic relaxation in Er3+ SIM in the presence of the ferromagnetic environment is analyzed. Incorporation of the [Er(HL)(L)]4CHCl3H2O complexes (L = DAPBH = 2,6-bis(phenylhydrazone)pyridine) to the ferromagnetic matrix consisting of PrDyFeCoB microparticles significantly changes magnetic relaxation in the Er3+ ions. Internal magnetic field of the magnetized ferromagnetic matrix delays spin relaxation in the Er3+ complexes in the absence of the external magnetic field. Compaction of the Er3+ complexes with ferromagnetic microparticles results in a composite material, in which magnetic relaxation is governed by Zeeman interaction of Er3+ spin with ferromagnetic microparticles possessing remnant magnetization at zero external field. Additional channel of microparticles effect on the magnetic relaxation is chemical interaction of the complexes with metallic surface of microparticles and corresponding orbital hybridization accelerating magnetic relaxation.

1.	M. Leuenberger et al. Quantum computing in molecular magnets // Nature. -2001.- 410. - P. 789.
2.	E. Dvoretskaya et al. Single ion magnets as magnetic probes of internal field in microparticle array // J. Phys. Chem. Sol. – 2021. – 157, - P. 110210.

The part of this work was supported by AU21UTAV01 UTILE ES 2021 funds.