Exchange Bias in a Layered Metal–Organic Topological Spin Glass

Abstract

The discovery of conductive and magnetic two-dimensional (2D) materials is critical for the development of next generation spintronics devices. Coordination chemistry in particular represents a highly versatile, though underutilized, route toward the synthesis of such materials with designer lattices. Here, we report the synthesis of a conductive, layered 2D metal–organic kagome lattice, Mn 3 (C 6 S 6 ), using mild solution-phase chemistry. Strong geometric spin frustration in this system mediates spin freezing at low temperatures, which results in glassy magnetic dynamics consistent with a rare geometrically frustrated (topological) spin glass. Notably, we show that this geometric frustration engenders a large, tunable exchange bias of 1625 Oe in Mn 3 (C 6 S 6 ), providing the first example of exchange bias in a coordination solid or a topological spin glass. Exchange bias is a critical component in a number of spintronics applications, but it is difficult to rationally tune, as it typically arises due to structural disorder. This work outlines a new strategy for engineering exchange bias systems using single-phase, crystalline lattices. More generally, these results demonstrate the potential utility of geometric frustration in the design of new nanoscale spintronic materials.

Ground-State Spin Dynamics in d1 Kagome-Lattice Titanium Fluorides

“…Therefore, 2-Ti with no detectable structural disorder and three SGL transitions is an intriguing quantum magnet. Similar magnetic behavior has also been observed recently in Mn 3 (C 6 S 6 ) with a kagome lattice, no obvious structural disorder, and a spin-glass transition . These compounds are distinct from the conventional canonical spin glass (CSG), since structural disorder is an important ingredient for conventional spin glass such as CuMn.…”

Low-Dimensional Metal–Organic Magnets as a Route toward the S = 2 Haldane Phase

“…Perhaps most excitingly, it has recently been demonstrated that redox-active radical ligands can introduce into MOFs both high electronic conductivity (0.45 S cm –1 ) and strong magnetic interactions, , despite the long distances between metal centers. This suggests that MOMs could form the basis for practical new quantum technology. − …”

Enhancement of Exchange Bias and Perpendicular Magnetic Anisotropy in CoO/Co Multilayer Thin Films by Tuning the Alumina Template Nanohole Size

“…Due to its interfacial origin, the magnitude of this loop shifts and the so-called exchange bias field ( H EB , defined as H EB = , in which H C1 and H C2 are the left and right coercive fields, respectively) is inversely proportional to the thickness of the FM layer [ 13 ]. In view of their peculiar properties, magnetic materials unveiling strong EB behavior have gained much interest owing to their widespread applications in sensors [ 14 ], spintronic devices [ 15 , 16 ], drug carriers [ 17 ], and magnetic read heads for magnetic information storage devices [ 18 ]. In addition, AFM/FM multilayer (ML) thin films with strong perpendicular magnetic anisotropy (PMA) have become a key factor in improving magnetic logic chips, spintronic devices, and random-access memory devices [ 19 , 20 , 21 ].…”