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Our R&D is not limited to the known crystal structures

 

The common approach in new material development is to focus on a well-known prototype structure and to apply brute force - by simply testing different element combinations. While some evolutionary improvement may occur, it hardly serves as a method for finding disruptive solutions.

 

Thin Film Materials

We developed and verified, in collaboration with the Center for Nanophase Materials Sciences (CNMS in Oak Ridge National Laboratory), a technologically competitive new class of insulating ferromagnetic thin film materials crystallizing in the ATO structure. Economic and environmental aspects were considered from the beginning in the material design. Various element combinations crystallize in the ATO-structure: magnetization and conductivity can be adjusted by controlling the composition. 

Our materials can be applied in tunable devices to simplify electronics. 

 

Magnetic ATO films grow excellently on oxidized silicon, silicon carbide, gallium nitride and optically transparent single crystals, such as lithium niobate, lithium tantalate  and sapphire and suit for multilayer device manufacturing

 

Magnetization of a few nm thick ATO films exceeds the value found in Y3Fe5O12 (YIG). We have also developed ferromagnetic thin film insulators from common, non-magnetic cations. When compared to the bulk material comprised from the same elements, we were able to increase the magnetization value by a factor of 100. The films preserve magnetization up to elevated temperatures and can be used in practical devices. The material is compatible with several high-k materials, including the one developed by Reciprocal Engineering - RE. Materials are transparent to visible light and can be applied in magneto-optic applications.

 

The functional properties of ATO films, such as magnetization and electrical resistivity, can be adjusted during the film growth while preserving the crystal structure and atomic scale metrics. This allows the fabrication of multilayer devices without detrimental interfaces: composition can continuously be adjusted during film growth. Films suit as platforms for ASL-circuits and devices. Notably the possibility to utilize the space in three dimensions is attractive. The ability to adjust magnetization, by either composition or strain, can be applied in the control of ferromagnetic resonance frequency (FMR). FMR dictates the operating  frequency of the RF-devices. Multilayer structures find applications in sensitive magnetic field sensors and spintronic applications.

 

Summary of the ATO materials can be downloaded here.

 

Advantages

Ferromagnetic insulators up to elevated temperatures. Materials which are ferromagnetic insulators up to and above 400 K can serve as a media for processing information in a form of spin waves induced in ferromagnetic media. Low losses in ferromagnetic insulators are due to the absence of Eddy currents - making the material very attractive alternative for metallic ferromagnetic layers and materials which are ferromagnetic insulators only at the lowest temperatures.

 

Better alternative for rare-earth element-, iron- and osmium-based compounds. Our materials are RoHS-compliant: they do not contain heavy metals or six-valent chromium. Besides, they do not possess rare-earth elements or iron.

 

Rare-earth elements (REE) are a subject to sudden price changes, though in many applications they can be replaced. Frequently, Yttrium (Y) is considered as a REE because it is frequently extracted from the same ore deposits as the REEs, and may face a supply shortfall.

 

Tellurium (Te), is extremely rare - and expensive - element, predicted by the United States Department of Energy (DoE) to suffer from a supply shortfall by 2025. It is among the elements avoided in our materials.

 

Iron (Fe) is a puzzling metallic impurity which is better to be avoided.

 

No osmium (Os) was applied, though there have been recent reports, including high-profile journals, according to which certain Sr- and Os-based perovskites, e.g., Sr3OsO6, are weakly magnetic. Unfortunately, due to the low magnetization values these compounds are often impractical. Also, Os is a very rare transition metal element, difficult to handle and forms toxic oxides.

 

We developed technologically viable, sustainable and environmentally
friendly thin film compounds without the aforementioned elements

 

For various applications, we provide both strongly magnetized ferromagnetic insulators and ferromagnetic conductors with excellent lattice matching through our processing technique. An example is given here.

 

By adjusting the growth parameters in-situ facilitates manufacturing via a smaller number of processing steps, without compromising the high crystalline quality of the films.

 

Applications

Examples are in IoT-technology, such as tunable RF-devices, antenna and waveguide structures, sensors, memories and all-spin logic (ASL) devices. Besides materials we design and test tunable RF-devices. Our focus is on fast, small and low-energy consuming solutions for the next generation devices operating at tens of GHz frequencies.