Tunable magnetic order in two-dimensional layered GdGe₂

Abstract

The arise of nanoscale spintronics has arouse keen interest in intrinsic ferromagnetism in two-dimensional (2D) materials. The intensive searching for 2D ferromagnets has been mainly focused on the 3d/4d transition...

2D magnetic phases of Eu on Ge(110)

“…16 This problem can be illustrated by a series of recent theoretical studies of 2D materials based on lattices of 4f 7 ions: Eu in EuGe 2 , 52 Eu in EuSi 2 , 53 and Gd in GdGe 2 . 54 They all suggest the 4f 7 ions in a monolayer to be fully spin-polarized, in contrast to the experiment 13,18 demonstrating strongly reduced magnetic moments. This significant unresolved problem makes it difficult to establish the mechanisms of spin-spin interaction in Eu lattices.…”

Spin filtering effect, thermal spin diode effect and high tunneling magnetoresistance in the Au/GdI2/Au van der Waals junction

“…21,23 This is not surprising, since the magnetic interactions are usually dependent on the number of layers, and this similar phenomenon was also recently found in the similar Gd alloy GdGe 2 , where bilayer GdGe 2 has the out-of-plane easy-magnetization direction, while the easy-magnetization direction is along the in-plane for monolayer GdGe 2 . 31 In addition, the easy-magnetization direction of CoX 2 (X = Cl, Br, I) also changes from the in-plane for the bulk to the out-of-plane for the monolayer. 32,33…”

“…21,23 This is not surprising, since the magnetic interactions are usually dependent on the number of layers, and this similar phenomenon was also recently found in the similar Gd alloy GdGe 2 , where bilayer GdGe 2 has the out-of-plane easy-magnetization direction, while the easy-magnetization direction is along the in-plane for monolayer GdGe 2 . 31 In addition, the easy-magnetization direction of CoX 2 (X = Cl, Br, I) also changes from the in-plane for the bulk to the out-of-plane for the monolayer. 32,33 Next, we calculated the bias-voltage-dependent spin-polarized current at the FM and AFM states for the vdW junction of Au/GdI 2 /Au, and in turn, the tunneling magnetoresistance (TMR) without and with a bias voltage can be obtained by (G FM − G AFM )/G AFM and (I FM − I AFM )/I AFM , respectively, where G FM (I FM ) and G AFM (I AFM ) are the total conductance (current) in the FM and AFM states, respectively.…”

Gadolinium Halide Monolayers: A Fertile Family of Two-Dimensional 4f Magnets

“…Although all the studies mentioned above are only theoretical predictions, they imply an effective strategy to take advantage of the highly localized f electrons to improve the magnetism: that is, utilizing the electrons on d orbitals as a medium. This strategy is not limited to Gd halides but is also effective for other Gd-based 2D materials …”

“…This strategy is not limited to Gd halides but is also effective for other Gd-based 2D materials. 69 Experimentally, monolayers of Gd halides can be obtained using two methods. One method is to synthesize their vdW bulks according to well-established chemical synthesis methods and then to exfoliate monolayers by a mechanical method.…”