Surface modification effects on coercivity of the CoFe_2O_4 thin films with different thickness La_(0.7)Sr_(0.3)MnO_3 layers

摘要

High coercivity CoFe_2O_4 (CFO) thin films with large-area are very desirable for applications. Here, we report La_(0.7)Sr_(0.3)MnO_3 (LSMO) layer decoration effects on coercivity in CFO thin films by solution processing. With LSMO layer decoration, the coercivity increases initially and then decreases with increasing LSMO layer thickness. Strain induced by the mismatched thermal expansion coefficient and magnetostrictive coefficient as well as the interfacial magnetic exchange coupling between CFO and LSMO are investigated. The room temperature out-of-plane and in-plane coercivity reached 7.6 and 4.9 kOe, respectively, are obtained, which are the highest values in solution derived CFO thin films. The improved coercivity is beneficial for applications and provides a facile route to enhance coercivity of CFO thin films through surface modification by soft magnetic layers.