  Manipulating the size and orientation of quantum materials is often used to
tune emergent phenomena, but precise control of these parameters is also
necessary from an experimental point of view. Various synthesis techniques
already exist, such as epitaxial thin film growth and chemical etching, that
are capable of producing specific sample dimensions with high precision.
However, certain materials exist as single crystals that are often difficult to
manipulate, thereby limiting their studies to a certain subset of experimental
techniques. One particular class of these materials are the lithium and sodium
iridates that are promising candidates for hosting a Kitaev quantum spin liquid
state. Here we present a controlled method of using a focused ion beam at
grazing incidence to reduce the size of a $\beta$-Li$_2$IrO$_3$ single crystal
to a thickness of 1 $\mu m$. Subsequent x-ray diffraction measurements show the
lattice remains intact, albeit with a larger mosaic spread. The integrity of
the magnetic order is also preserved as the temperature dependent magnetic
diffraction peak follows the same trend as its bulk counterpart with a
transition temperature at TN = 37.5 K. Our study demonstrates a technique that
opens up the possibility of nonequilibrium experiments where submicron thin
samples are often essential.
