Magnetic properties of nanosized γ-Fe2O3 and α-(Fe2/3Cr1/3)2O3, prepared by thermal decomposition of heterometallic single-molecular precursor

► Thermolysis of Fe2Cr complex leads to γ-Fe2O3 or α-(Fe2/3Cr1/3)2O3 nanoparticles. ► Formation of certain phase depends on the process temperature. ► Formation temperature growth leads to abrupt change in particles size and magnetism. ► Particles formed at low temperatures possess typical superparamagnetic behavior. ► Particles formed at high temperatures are antiferromagnetic.