Magnetism Induced by Nitrogen Doping in Ferroelectric HfO₂

HfO₂ has been widely used in the electronic device industry because of the high-k characteristics of the tetragonal phase. Furthermore, the discovery of the ferroelectric orthorhombic Pca2₁ HfO₂ in 2011 has aroused both academic and industrial interest up to date.¹ In addition to these high-k and ferroelectric properties, HfO₂ was expected to have the magnetism when hole is doped by substituting nonmagnetic atom or vacancy for hafnium.^2,3 Inspired by previous magnetic-related studies of HfO₂, we found an intriguing low-dimensional anti-ferromagnetism (AFM) induced by N-doping for oxygen sites. We will discuss how to convert the AFM to ferromagnetism by employing external perturbations such as epitaxial strain in order to tailor the commercial ferroelectric HfO₂ as a suitable candidate for magnetoelectric device.<br/><br/>[1] T. S. Böscke, J. Müller, D. Bräuhaus, U. Schröder, and U. Böttger, Appl. Phys. Lett. 99(10), 102903 (2011).<br/>[2] Chaitanya Das Pemmaraju and S. Sanvito, PRL 94, 217205 (2005)<br/>[3] Hongming Weng and Jinming Dong, PHYSICAL REVIEW B 73, 132410 (2006)