Tailor made magnetic sensors

We use our thin-film capability to make bespoke magnetic sensors for niche applications where existing commercial sensors are not sufficient.

The science

We make thin-film devices—mostly thin-film magnetic devices or sensors—by depositing thin layers (somewhere from 100 nanometres and thinner) onto solid substrates. The magnetic materials can be deposited as a single layer so that the properties of a particular composite material can be studied. If deposited in alternating layers of magnetic and nonmagnetic materials, the 'stack' can be used as a sensor device.

Impact and potential

The Institute has the capability to make bespoke magnetic sensors. We tailor our sensors to solve problems for which off-the-shelf sensors would not be adequate.

For example, we can make magnetic sensors that can alter their direction of sensitivity to the field. Such sensors are useful in applications in which a small field change against a large background field needs to be detected. In eddy testing of metal objects, for example, a large field may be applied in order to generate a smaller induced field, and it is the induced field that needs to be measured.

Bespoke sensors could also be tuned or controlled to detect an object’s magnetic field, even in an environment where there was a large background magnetic field. Another application could be looking for multiple different magnetic signatures. There could be applications of this technology in navigation, sensing buried metallic magnetic objects, or in monitoring the current in electric vehicle batteries.

Capabilities

• Technique of depositing these films is magnetron sputtering
• Etch patterns or devices using an ion mill
• Wire bonder
• SQUID and PPMS systems
• Magneto-optical Kerr Effect (MOKE) to measure the magnetic properties of materials

The people

Dr Simon Granville manages the thin film deposition and magnetic properties labs, which include a SQUID magnetometer, PPMS, and MOKE equipment. He believes the Institute is unparalleled in New Zealand, with the necessary expertise and capability to take leading-edge materials science and engineering and create new tools and prototypes that solve intractable industry problems.