Gopalan Srinivasan
Oakland University, MI·Materials Science
Phones and wireless networks rely on small devices that filter and process high-frequency signals. Ferrites and garnets, magnetic oxide materials that waste little signal energy, are excellent for these devices.
- Fields
Materials Science
Physics
Engineering
- Topics
ferrites
garnets
yttrium iron garnet
- Grants
- 1 known grant, through Jun 2027
What they work on
- Grow yttrium iron garnet and nickel ferrite films by liquid phase epitaxy on polycrystalline substrates with a large crystal mismatch, using combinatorial substrate epitaxy to survey many strain states at once.
- Identify which substrate grain orientations give the largest strain-induced internal magnetic field, using localized ferromagnetic resonance measured by scanning microwave microscopy together with electron microscopy.
- Bond magnetic films on the preferred substrates to ferroelectric layers such as lead zirconate titanate, so that voltage can tune their magnetism through magnetoelectric coupling.
- Build and test 1–20 GHz resonators and band-pass and band-stop filters from these composites, measuring tuning by voltage and by permanent magnet, signal loss, and suitability for 4G/5G.
More about the research
Making the devices tunable to different frequencies usually requires a strong external magnet, which makes them bulky and power-hungry. This international collaborative project proposes to remove that magnet. It will build a strong internal magnetic field into thin films of the material itself, and it will allow the device to be tuned by voltage rather than by a magnetic field.
Why it matters
Tunable microwave devices that need no large magnet and use less power could make wireless hardware smaller and more energy efficient. The resonators and filters developed here could benefit makers of consumer electronics and communication systems, including 4G/5G technologies. An industry partner will judge whether they are practical in real products.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Julius De Rojas
Oklahoma State University, OK·Physics
Establish how voltage-driven migration of oxygen and lithium ions (magneto-ionics) changes spin-wave behavior in magnetic thin films, producing large changes that persist without power, measured with Brillouin light scattering and ferromagnetic resonance.
Abdellah Lisfi
Morgan State University, MD·Materials Science
Test whether two-phase nanostructures break the spin-orbit coupling link to produce large magnetostriction with weak anisotropy in Fe-Ga-based alloys containing aluminum or germanium.
Keji Lai
University of Texas at Austin, TX·Physics
Measure the effective permittivity of excitons in monolayer semiconductors using cryogenic laser-illuminated microwave impedance microscopy, a scanning probe that senses local electrical response under light.
The school
Oakland University: 5 labs on PI Pages, $39M a year on research, 60 research doctorates a year.
Reach out
A start for your email. Fill in the brackets.