  Phase-separated magnetic fluids provide a very strong magnetic response
($\mu>25$) in a liquid state material. Even small fields can cause a notable
material response, but this depends on its properties, which are often
difficult to control. Here, we investigate how temperature affects the
properties of the system, where phase separation is induced by an increase in
ionic strength. Following the deformations of individual microscopic droplets,
we can extract surface tension, magnetic permeability, and viscosity. We find
that the temperature increase does not affect the surface tension, while the
magnetic permeability and viscosity increase. Applying this knowledge to induce
a shape instability for a drop only using temperature shows the potential of
applicability of our findings.
