DNA-Immobilized CoFe₂O₄ Magnetic Nanoparticles: A Nature-Friendly Material Manifesting Negative Differential Resistance and Hysteresis Effects

Negative differential resistance (NDR) and hysteresis effects have been successfully achieved by synthesizing DNA-immobilized CoFe ₂ O ₄ magnetic nanoparticles using wet chemical co-precipitation method. These multiple effects in a single compound particle can open the door for several next generation applications from high frequency communication device development to memory storage device. Here, for both positive and negative bias condition during electrical characterization, reproducible NDR peaks have been found. For the sample with maximum DNA conjugation with CoFe ₂ O ₄ magnetic nanoparticles consistent hysteresis effects have also been found. Both of these features i.e., NDR and hysteresis can be attributed to conformational changes in crystal structure due to addition of DNA and polaron transform phenomena at the molecular level, respectively. By achieving these two features in one material, multifunctional devices can be developed for molecular electronic applications.