Spintronics is a field of condensed matter physics that studies phenomena in
which both spin and charge of an electron play an important role. In the
past spintronics has focused largely on ferromagnetic materials, however,
recently also antiferromagnetic materials has attracted interest.
Antiferromagnets are materials which have a long range magnetic order such
that the net magnetic moment is zero. They have some advantages over
ferromagnets such as very fast magnetic dynamics and wide range of available
materials. Using antiferromagnets is challenging because the
antiferromagnetic order is hard to manipulate and detect, however, with the
advent of spintronics a new possibilities emerge, such as electrical or
optical detection and manipulation. Here we discuss a new method which
allows for electrical manipulation of the antiferromagnetic order. The
method is based on the so-called spin-orbit torque, which is known to exist
in ferromagnets with broken inversion symmetry. We demonstrate that this
method can also be used in antiferromagnets, however, the symmetry
requirements are different. In particular a local, rather than a global,
inversion symmetry breaking is necessary. We calculate the spin-orbit torque
in several antiferromagnetic crystals and also discuss the experiments which
have demonstrated switching of an antiferromagnetic order using this method.