Questioning the validity of spintronic inductors: Potential artifacts in emergent inductance

Understanding and utilizing spin–charge interactions in solids is a cornerstone of spintronics. Emergent inductance, a notable consequence of these interactions, has been observed in various spintronic devices. Typically, it is characterized by a negative inductance at low frequencies and significant suppression at high frequencies due to external pinning effects. However, we demonstrate that these conditions are not exclusive to emergent inductance as parasitic circuit elements can mimic these effects. We find that hidden parasitic capacitance significantly influences the imaginary impedance by forming a parallel resister (R)-capacitor (C) circuit. Additionally, magnetoresistance in the RC circuit alters imaginary impedance magnetically, which also mimics the anisotropic behavior of emergent inductance. These observations suggest that parasitic elements may hinder the observation of pure emergent inductance. Therefore, stricter criteria are required to confirm emergent inductance.