Tailorable magnetic properties of ε-Fe2O3/SiO2 hybrid via alkaline etching

In this study, conventional silicon alkaline-etching procedure was utilized to tailor magnetic properties of ε-Fe2O3/SiO2 hybrid. It was found that the saturation magnetization, coercivity and exchange bias field can be readily changed and tailored by altering the etching time and frequency in a set of sodium hydroxide solutions. The relative quantity of ε-Fe2O3 phase, the proximity or pinning effect derived from SiO2 phase as well as the phase transformation from ε-Fe2O3 to α-Fe2O3 during etching treatment were three main factors to its controllable magnetic properties. This work will shed new light on the development of functional ε-Fe2O3/SiO2 composites with tailorable magnetism in practical magnetically-relevant applications.