Sprecher
Beschreibung
The Fe$_3$O$_4$/Nb:STO system has gathered significant attention due to its potential application in spintronics and memristors. The interface between Fe$_3$O$_4$ and Nb:STO plays a crucial role in determining the overall electronic and magnetic properties of the system. We present an investigation of a 30 nm Fe$_3$O$_4$ thin film on a TiO$_2$ terminated Nb-doped SrTiO$_3$ (TiO$_2$-Nb:STO) substrate deposited by pulsed laser deposition (PLD), focusing on the buried interface using Polarized Neutron Reflectometry (PNR), X-ray Magnetic Circular Dichroism (XMCD), and X-ray Reflectometry (XRR).
Our study utilizes XRR to assess the structural properties, including roughness and density variations, across the interface. PNR is employed to probe the magnetic depth profile. The combination of these techniques reveals a 1 unit cell (u.c.) $\gamma$-Fe$_2$O$_3$ interlayer between the Fe$_3$O$_4$ thin film and the Nb:STO substrate and a 2 u.c. $\gamma$-Fe$_2$O$_3$ surface layer. XMCD provides element-specific magnetic information throughout the entire system, confirming the total thickness of $\gamma$-Fe$_2$O$_3$ to be 3 u.c.
The results reveal significant modifications in the magnetic and structural properties at the buried interface, driven by interactions between the Fe$_3$O$_4$ film and the TiO$_2$-Nb:STO substrate. Specifically, the presence of the $\gamma$-Fe$_2$O$_3$ interlayer and surface layer affects the magnetic coupling of the system.
