Electrical Control of Magnetic Resonance in Phase Change Materials

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Metal-insulator transitions (MITs) in resistive switching materials involve significant electrical response changes.
• Distinct magnetic characteristics in these phases lead to altered spin excitations.
• La_0.7Sr_0.3MnO₃ (LSMO) exhibits a ferromagnetic metallic state at low temperatures and a paramagnetic insulating state above room temperature.

Purpose of the Study:

• To investigate the magnetic phase separation and spin excitation resonances in LSMO under electrical bias.
• To explore the potential of voltage-triggered MITs for tuning magnetic resonance characteristics.
• To assess the applicability of these findings for neuromorphic circuit applications.

Main Methods:

• Spin-transfer ferromagnetic resonance (ST-FMR) spectroscopy was employed.
• Electrical bias was applied to LSMO samples below the critical MIT threshold.
• Systematic variation of spin-excitation resonances with applied bias was analyzed.

Main Results:

• Magnetic phase separation was observed in LSMO even for electrical biases below the critical value for MIT.
• Spin-excitation resonances showed systematic variations correlated with the applied electrical bias.
• Voltage-triggered MITs were demonstrated to effectively alter magnetic resonance characteristics.

Conclusions:

• Electrical bias can induce magnetic phase separation and tune magnetic resonance in LSMO below the MIT critical bias.
• These findings provide an effective method for tuning synaptic weights in neuromorphic circuits.
• The study highlights the interplay between electrical stimuli, MITs, and magnetic properties in advanced materials.