Mn2FeSi: An antiferromagnetic inverse-Heusler alloy

Search for low-moment magnetic materials with high spin-polarization is important for emerging spintronics applications. In this work, we have conducted detailed growth and characterization along with complementary first-principles calculations to investigate the structure and magnetism of Mn2FeSi, which is a prospective inverse-Heusler material. We confirm that Mn2FeSi adopts a cubic inverse-Heusler structure, in excellent agreement with theory. The magnetic and resistivity measurements show an antiferromagnetic behavior with a Néel temperature of 48 K, which is consistent with prior experimental reports. We find that a low-moment state with higher ordering temperature (150–200 K) can be stabilized under certain growth conditions. Supporting calculations show that Neel-type antiferromagnetic states are energetically very close to the ferrimagnetic ground state. Our work provides evidence that Mn2FeSi may be interesting for exploring newer applications with low-moment materials, but the ordering temperatures are low for viable practical applications.