Slow-Relaxation Behavior of a Mononuclear Co(II) Complex Featuring Long Axial Co-O Bond

Abstract

Co(II) mononuclear complex with different coordination geometry would display various of field-induced single-ion magnet (SIM) behaviors. Here, we identify a field-induced single-ion magnet in a mononuclear complex Co(H2DPA)2·H2O (H2DPA = 2,6-pyridine-dicarboxylic acid) by the hydrothermal method. The long axial Co-O coordination bond (Co1‧‧‧O3) can be formed by Co1 and O3. Therefore, Co(II) ion is six-coordinated in a distorted elongated octahedron. AC magnetization susceptibilities show that the effective energy barrier is up to 43.28 K. This is much larger than most mononuclear Co(II). The distorted elongated octahedron caused by the axial Co-O coordination bond is responsible for the high effective energy barrier. The distribution of electron density in Co1 and O3 atoms in the long axial bond would influence the magnetic relaxation process in turn. Our work deepens the relationship between the effective energy barrier and the weak change of ligand field by long axial bonds, which would facilitate constructing SIM with high energy temperature.

Enhancing Photoluminescence of CsPb(ClxBr1−x)3 Perovskite Nanocrystals by Fe2+ Doping

“…The incorporation of appropriate impurity ions into host lattices has been exploited as a promising method to stabilize the crystallographic phases while modulating the optical, electronic, and magnetic properties of diverse semiconductors [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Regarding the halide perovskites, the partial substitution of Pb 2+ by divalent metal ions, such as Cu 2+ , Mg 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Mn 2+ at the B sites of the perovskite lattice have been demonstrated [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Klug et al revealed that the perovskite films retain an excellent photovoltaic performance if less than 3% Pb 2+ ions are substituted by homovalent metal species due to the high tolerance of the perovskite lattices [ 31 ].…”