Nanosized neck-structured alpha-Fe2O3 nanoparticles were prepared successfully from iron(II) chloride tetrahydrate solely by hydrothermal method. FE-SEM and TEM studies revealed a unique necked structure with a particle size of ca. 50-60 nm. The synthesized nanomaterials showed excellent colloidal stability and magnetization ability. Finally, the as-prepared alpha-Fe2O3 nanoparticle suspensions showed almost 100% cancer cell killing by the significant temperature increment when an AC (alternating current) magnetic field and photoirradiation were applied at a concentration of 80 mu g mL(-1) MEM (minimum essential medium).