Hexaferrite can be magnetized or have an internal magnetisation do you want to measure them with or without that static magnetic field. You coould consider making a microwave printed circuit on a hexaferrte substrate say 1 mm thick.

Hexaferrite samples for microwave absorption studies can be prepared in a variety of ways. The most common method is the solid-state method, which involves mixing the appropriate oxides together and then heating them to a high temperature. Another common method is the sol-gel method, which involves mixing the oxides in a solution with a gelling agent and then drying the gel to form a powder.

The specific method used to prepare hexaferrite samples will depend on the desired properties of the samples. For example, the solid-state method is typically used to prepare samples with a high density, while the sol-gel method is typically used to prepare samples with a small particle size.

Once the hexaferrite samples have been prepared, they must be formed into pellets or other shapes for microwave absorption studies. This can be done by pressing the powdered samples into pellets or by casting them into molds. The pellets or shapes should then be sintered at a high temperature to improve their strength and density.

The following is a more detailed description of the solid-state method for preparing hexaferrite samples for microwave absorption studies:

The following is a more detailed description of the sol-gel method for preparing hexaferrite samples for microwave absorption studies:

Once the hexaferrite samples have been prepared, they can be characterized using a variety of techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The microwave absorption properties of the samples can then be measured using a vector network analyzer (VNA).

Thanks for your answer. I have already synthesized the pellets. But I want to know how to make the contacts to measure microwave absorption. Or is it not necessary to make the contacts on pellets? (For dielectric studies, contacts are usually made using silver paste).

Dear Nishkala Rao,

It depends on the method of measurement using VNA. For example, if you use NWR (Niccolson-Ross-Weir) samples can be used without any contacts. The shape of the samples should fit the microwave waveguide. If you want to measure by different method, for example, using microstrip line (as it was mentioned by Dr. Fritz Caspers) you should make contacts on the surface of sample.

i used coaxial method where you use two different kind of pellets for measurements of permittivity and permeability.

For permittivity, you make a cylinderical pellet of 1-3mm in thickness (dia depends on the fixture/holder you are using, specified by the machine standards )

For permeability, you use a donut shaped pellet. Again the inner and outer dia varies, depending on the machine specifications.

You have to design your own die using tool steel, that can withstand 5-10 tons of pressure atleast..

mix a little bit of paraffix wax with the samples(paraffix is transparent to microwave spectrum) to make them less brittle and make the pellets accordingly using hydraulic press.

Thanks for the answer