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The magnetic tunnel junction (MTJ) based molecular spintronics device (MTJMSD) approach is suitable for mass production. This approach provides solutions to fabrication difficulties related to reliably connecting molecular device elements to the ferromagnets (FMs). To producing MTJMSD, the molecular channels are bridged across the insulator of an MTJ testbed with exposed side edges. In an MTJMSD, two FMs are simultaneously connected by an insulator film and the molecular channels along the exposed sides. In our prior experimental studies, we observed that molecules could produce strong coupling between ferromagnets in the presence of the competing coupling via an insulator. In this paper, our Monte Carlo Simulation (MCS) was used to study the impact of coupling variation via insulator (a.k.a. Ji) on the magnetic properties of an MTJMSD. We studied the effect of Ji while varying the molecule induced antiferromagnetic exchange coupling. The ferromagnetic or antiferromagnetic nature and magnitude of Ji determined the resultant effect. Antiferromagnetic Ji enhanced the pre-existing antiferromagnetic molecular coupling effect. Ferromagnetic Ji competed with the opposite nature of antiferromagnetic molecular coupling. Our MCS may help to understand the impact of insulator thickness and defects on the molecular spintronics device performance and design process.
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Gate control of interlayer exchange coupling in ferromagnetic semiconductor trilayers with perpendicular magnetic anisotropy
Interlayer exchange coupling (IEC) has been intensively investigated in magnetic multilayers, owing to its potential for magnetic memory and logic device applications. Although IEC can be reliably obtained in metallic ferromagnetic multilayer systems by adjusting structural parameters, it is difficult to achieve gate control of IEC in metallic systems due to their large carrier densities. Here, we demonstrate that IEC can be reliably controlled in ferromagnetic semiconductor (FMS) trilayer structures by means of an external gate voltage. We show that, by designing a quantum-well-type trilayer structure based on (Ga,Mn)(As,P) FMSs and adapting the ionic liquid gating technique, the carrier density in the nonmagnetic spacer of the system can be modulated with gate voltages of only a few volts. Due to this capability, we are able to vary the strength of IEC by as much as 49% in the FMS trilayer. These results provide important insights into design of spintronic devices and their energy-efficient operation.
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- Award ID(s):
- 1905277
- PAR ID:
- 10594692
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- APL Materials
- Volume:
- 10
- Issue:
- 4
- ISSN:
- 2166-532X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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