DG-13 Magneto-Ionically Tuning the Magnetization and Exchange Bias in all-solid-state CoMnN Heterostructures
Creators: Nicolau Lopez-Pinto
Publisher: name: IEEE
Year: 2025

The rapid growth of nanoelectronics and integration of artificial intelligence on the internet of things demand innovative materials for faster, energy-efficient data storage and processing. Magnetism is central for this purpose, as typically devices switch between two states. Magnetic fields or spin polarized electric currents are commonly employed for the purpose, both of which have considerable energy losses by heat dissipation. To minimize these detrimental effects recent research explores the use of electric fields as an alternative. Magneto-ionics (MI) has proven successful in tuning magnetic properties in a remarkable, non-volatile manner. MI has been broadly investigated in oxygen-based systems, despite other mobile ions (H+, OH-, Li+ or N3-) also showing potential. For instance, nitrogen-based MI induces larger changes with lower threshold voltages than its oxygen counterpart when gated in propylene carbonate-based electrolytes.1,2 Nonetheless, solid-state structures are preferred for device applications, a domain where nitrogen MI lacks research. In this work, we report a 110% increase in saturation magnetization in an all-solid-state Ta/Co0.55Mn0.45N/Ta heterostructure by means of voltage-driven nitrogen ion transport towards the bottom Ta reservoir layer, correlating the observed magnetic changes to the structural and chemical modification of the ternary phase.3 Furthermore, the sample exhibits exchange bias (EB) below 30 K, confirming the presence of multiple nitride phases, which are modified upon gating. Additional compositions were also studied, which, after being coupled to a Co FM layer, exhibited variable EB at room temperature or below, depending on the composition. The EB was later modified following a voltage treatment, showing a modest modification of the interfacial phenomenon at RT, while a large change is observed at low temperatures (down to 100 K). Further experiments are currently being carried out to fully understand the coupling behavior after voltage treatment. These findings suggest a pathway for non-volatile control of magnetic properties in nitride compounds, which is appealing for energy-efficient spintronic devices compatible with CMOS technology.References: [1] J. de Rojas, et al., Nat. Commun. 11, 5871 (2020). [2] Z. Tan, et al., ACS Appl. Mater. Interfaces 14, 44581 (2022). [3] N. López-Pintó, et al., Adv. Func. Mater., 2024, 2404487.
The rapid growth of nanoelectronics and integration of artificial intelligence on the internet of things demand innovative materials for faster, energy-efficient data storage and processing. Magnetism is central for this purpose, as typically devices switch between two states. Magnetic fields or spin polarized electric currents are commonly employed for the purpose, both of which have considerable energy losses by heat dissipation. To minimize these detrimental effects recent research explores the use of electric fields as an alternative. Magneto-ionics (MI) has proven successful in tuning magnetic properties in a remarkable, non-volatile manner. MI has been broadly investigated in oxygen-based systems, despite other mobile ions (H+, OH-, Li+ or N3-) also showing potential. For instance, nitrogen-based MI induces larger changes with lower threshold voltages than its oxygen counterpart when gated in propylene carbonate-based electrolytes.1,2 Nonetheless, solid-state structures are preferred for device applications, a domain where nitrogen MI lacks research. In this work, we report a 110% increase in saturation magnetization in an all-solid-state Ta/Co0.55Mn0.45N/Ta heterostructure by means of voltage-driven nitrogen ion transport towards the bottom Ta reservoir layer, correlating the observed magnetic changes to the structural and chemical modification of the ternary phase.3 Furthermore, the sample exhibits exchange bias (EB) below 30 K, confirming the presence of multiple nitride phases, which are modified upon gating. Additional compositions were also studied, which, after being coupled to a Co FM layer, exhibited variable EB at room temperature or below, depending on the composition. The EB was later modified following a voltage treatment, showing a modest modification of the interfacial phenomenon at RT, while a large change is observed at low temperatures (down to 100 K). Further experiments are currently being carried out to fully understand the coupling behavior after voltage treatment. These findings suggest a pathway for non-volatile control of magnetic properties in nitride compounds, which is appealing for energy-efficient spintronic devices compatible with CMOS technology.References: [1] J. de Rojas, et al., Nat. Commun. 11, 5871 (2020). [2] Z. Tan, et al., ACS Appl. Mater. Interfaces 14, 44581 (2022). [3] N. López-Pintó, et al., Adv. Func. Mater., 2024, 2404487.