Temperature dependence of tunnel magnetoresistance in flexible magnetic tunnel junctions

Flexible spintronic devices hold significant potential for applications in wearable electronics and other emerging fields due to their excellent mechanical flexibility. However, most studies on the temperature dependence of magnetic tunnel junctions (MTJs) have primarily focused on rigid silicon-based substrates, while systematic investigations of flexible MTJs remain limited. This study systematically examines the temperature dependence of the tunnel magnetoresistance (TMR) ratio, the parallel (P) and the antiparallel (AP) resistance, and dynamic conductance of MTJs fabricated on polyimide (PI) substrates. Our experimental results demonstrate that the temperature-dependent behavior of TMR in flexible MTJs closely resembles that of conventional silicon-substrate MTJs. This finding suggests that optimization strategies for rigid MTJs structures can be applied to flexible MTJs, accelerating the development of flexible spintronics. We also observe a significant reduction in the coercivity of flexible MTJs at low temperatures, a trend that contrasts with the coercivity variation in silicon-based MTJs. This distinct feature provides an alternative approach for tuning flexible MTJs and provides new design insights for future stress-controlled spintronic devices.