Giant Piezomagnetism in Mn₃NiN

Area of Science:

• Solid State Physics
• Materials Science
• Spintronics

Background:

• Controlling magnetism via electric fields or strain is crucial for spintronics.
• Giant piezomagnetism, a linear magneto-mechanic coupling, is a key phenomenon.
• Antiferromagnetic materials with geometric frustration are promising candidates for novel devices.

Purpose of the Study:

• To demonstrate giant piezomagnetism in antiperovskite Mn3NiN.
• To explore the potential of Mn3NiN for new memory device concepts.
• To investigate the magneto-mechanic coupling effects in strained Mn3NiN films.

Main Methods:

• Fabrication of Mn3NiN films with controlled intrinsic biaxial strains.
• Growth of Mn3NiN films on BaTiO3 substrates to induce uniaxial strain.
• Measurement of Néel transition shifts and magnetization changes under strain.
• Characterization of strain coupling efficiency and magnetoelectric coefficient.

Main Results:

• Intrinsic biaxial strains of ±0.25% shifted the Néel transition by up to 60 K.
• Films on BaTiO3 exhibited a significant magnetization jump due to uniaxial strain.
• An inferred strain coupling efficiency of 44% and a magnetoelectric coefficient α of 0.018 G cm/V were measured.
• The observed magnetoelectric coefficient showed a 1000-fold increase compared to Cr2O3.

Conclusions:

• Giant piezomagnetism is confirmed in antiperovskite Mn3NiN, driven by geometric frustration.
• The material shows potential for advanced spintronic memory applications.
• Further research into Mn-based antiperovskites may yield even larger piezomagnetic effects at room temperature.