Room-Temperature Multiferroicity and Magnetization Dynamics in Fe/BTO/LSMO Tunnel Junction

This article describes the static, dynamic, and temperature dependent magneto-transport properties of the Fe/BTO/LSMO mutliferroic tunnel junction (MFTJ). The multilayer structure is grown on a high quality crystalline STO substrate by means of pulsed laser deposition, which enables epitaxial layer-by-layer growth. The MFTJ is patterned into micrometer-size devices by means of the ion-etching-free lithography process ensuring that the properties of the oxide layers are preserved after the device fabrication. The measured static properties indicate that the MFTJ has multiferroic properties at room temperature with the tunneling electroresistance (TER) and tunneling magnetoresistance (TMR) reaching 270% and 0.4%, respectively. The temperature measurements indicate the exponentially decreasing dependence of TMR with increasing temperature, whereas TER is temperature independent. The electric ferromagnetic resonance measurements based on the spin-diode effect shows the existence of two resonance peaks, from both ferromagentic electrodes, one identified as LSMO-derived and characterized by low magnetization damping of alpha = 0.002 and the other from the Fe.