Ferromagnetism of Co-Doped Titanate and Anatase Nanorods Before and After Lithium Intercalation

Abstract

Co-doped titanate nanorods are synthesized via a one-step hydrothermal reaction. Calcining the titanate nanorods at 700 °C for 2 h in an argon atmosphere yields Co-doped anatase (TiO2) nanorods. The calcined nanorods are straight, with lengths over 2 μm and diameters between 80 and 120 nm as measured by transmission electron microscopy (TEM). The presence of the cobalt element in a bundle of titanate nanorods is confirmed by energy dispersive X-ray spectrum (EDS) and inductively coupled plasma (ICP). The obtained Co-doped titanate and titania nanorods exhibit ferromagnetism at 300 K. Structural and magnetic analyses reveal that the Co ions intercalated into the layers of nanorods and the ferromagnetic response could be attributed to the intrinsic properties of the nanorods. The electrochemical lithium intercalation of the as-prepared titanate nanorods and calcined anatase nanorods was conducted by a galvanostatic method. The results suggest that the lithium intercalation has a different influence on the magnetic properties for Co-doped titanate nanorods and anatase nanorods. In particular, the magnetization of Co-doped anatase nanorods reaches to the maximum value after Li intercalation with the Li/Ti intercalation ratio of 0.075.