Enhanced magnetic remanence and electron mobility in (100)-epitaxial NdN thin films

Abstract

We report a systematic study of the epitaxial growth of (100)-oriented NdN thin films on (100)LaAlO3 substrates, focusing on the effect of growth temperature on crystal quality under moderate molecular nitrogen pressure. In situ reflection high-energy electron diffraction monitoring reveals a narrow streaky pattern for the highest quality film with a FWHM of 0.99° in the rocking curve. Reflection high-energy electron diffraction and ϕ-scans confirm the 45° in-plane rotational alignment of NdN on LaAlO3, consistent with other rare-earth nitrides. Magnetic hysteresis measurements show significant enhancement in remanence, increasing from 52% in the polycrystalline film to 93% in the epitaxial film, while electrical measurements give an electron mobility of ∼140 cm2 V−1 s−1 at 2 K, a tenfold increase compared to polycrystalline films. At temperatures above 375 °C, we observe a reaction with the substrate that leads to the formation of an interfacial Nd2O3 layer.