Charging ahead
Under project AMORE (Advanced Magnetic Oxides for Responsive Engineering) a new method of fabrication of ferromagnetic half metal oxides has been developed. Ferromagnetic materials are materials, which exhibit a spontaneous magnetisation, due to the influence of electron spin. The spin of an electron has a magnetic dipole moment and creates a magnetic field. Only atoms with unpaired electrons (partially filled shells) can experience a net magnetic moment from spin. A ferromagnetic material has many such electrons and if they align they create a measurable macroscopic field. Above a certain temperature, the Curie temperature, the material ceases to be ferromagnetic. Zinc oxides (ZnO, ZnCrO) were formed by oxidation of sputter- deposited zinc nitride doped with Cr. With this fabrication method the oxides proved to have superior electrical properties and high Curie temperatures. A method of coating (surface passivation) was also developed to protect the materials from contamination and to maintain their conductivity over a period of months. One of the oxides produced has a high level of transmittance, which is promising for use in transparent electronics in devices such as flat panel displays and solar cells. The ease of manufacture also opens up doors for utilising the materials in spintronics applications. Also known as magnetoelectronics, this is an emerging science, which exploits the propensity of electrons to spin, as well as making use of their charge.
