Embedding atomic cobalt into graphene lattices to activate room-temperature ferromagnetism

Abstract

Graphene is extremely promising for next-generation spintronics applications; however, realizing graphene-based room-temperature magnets remains a great challenge. Here, we demonstrate that robust room-temperature ferromagnetism with TC up to ∼400 K and saturation magnetization of 0.11 emu g−1 (300 K) can be achieved in graphene by embedding isolated Co atoms with the aid of coordinated N atoms. Extensive structural characterizations show that square-planar Co-N4 moieties were formed in the graphene lattices, where atomically dispersed Co atoms provide local magnetic moments. Detailed electronic structure calculations reveal that the hybridization between the d electrons of Co atoms and delocalized pz electrons of N/C atoms enhances the conduction-electron mediated long-range magnetic coupling. This work provides an effective means to induce room-temperature ferromagnetism in graphene and may open possibilities for developing graphene-based spintronics devices.

Two-dimensional binary transition metal nitride $M$N$_4$ ($M$ = V, Cr, Mn, Fe, Co) with a graphene-like structure and strong magnetic properties

“…The planar M N 4 (M =metal) moiety embedded in graphene sheet acting as single atom catalyst has been identified experimentally [3][4][5], in which more than twenty different metals, including noble metals and nonnoble metals, are employed to synthesize the M N 4graphene structure. Very recently, the room-temperature ferromagnetism in CoN 4 -graphene systems has been observed [6]. In theoretical studies, the planar cobalt carbonitrides CoN 4 C 10 , Co 2 N 8 C 6 , Co 2 N 6 C 6 , and CoN 4 C 2 are predicted and their stability is confirmed by the firstprinciples calculations [7,8].…”

Two-Dimensional Conductive π–d Frameworks with Multiple Sensory Capabilities

“…Two-dimensional (2D) materials with outstanding structural, chemical, and physical properties − have attracted intensive attention in the past decade, promising for technological applications. − Compared with 2D inorganic materials, increasing efforts have been committed to organic π-conjugated nanosheets prepared by self-assembly due to their diversity of physical and chemical properties and topological structure. , In this context, 2D molecular frameworks are reliant on the coordination chemistry between chelating units that result in the hybridization of the d-orbits of transition metals and frontier orbits of conjugated aromatic ligands containing functional groups such as hydroxy group, amino group, and sulfhydryl group. For instance, a 2D π–d conjugated coordination Cu-BHT (benzenehexathiol) system has shown high electrical conductivity, while 2D Cu 2 (TCPP) (TCPP = meso-tetra­(4-carboxyphenyl)­porphine) has been applied to electronic devices .…”

Achieving high-temperature ferromagnetism by means of magnetic ions dimerization

“…[14] Very recently, robust roomtemperature ferromagnetism with T C up to 400 K has been realized in CoN 4 -embedded graphene. [15] In theoretical studies, CrI 3 [16], CrGeTe 3 [17], Fe 2 Si [10], MnS 2 [18], Fe 3 P [19], CrMoS 2 Br 2 [20], GdI 2 [21], CrN 4 C 2 [22] monolayers are predicted to be 2D ferromagnet with high Curie temperature.…”

“…So, the dynamical and thermal stability of Mn 2 N 6 C 6 is verified. In fact, the structure of Mn 2 N 6 C 6 is similar to the MnN 4 -embedded graphene sheets, which have been synthesized in a great number and widely studied in previous theoretical and experimental works [15,[35][36][37][38][39].…”