Magnetostriction and Piezomagnetism in non-collinear antiferromagnets: NiS₂ and MnTe₂

Magnetostriction is the property of ferromagnetic materials to change shape when magnetized. This effect, observed in materials like iron, nickel, and cobalt, results in physical expansion or contraction in response to a magnetic field, enabling a range of applications, including actuators, sensors, and the generation of sound or vibration. Magnetostriction has been widely studied in ferromagnets using dilatometry. Recently, however, strong magnetostrictive effects have also been observed in antiferromagnets. In addition, piezomagnetism—the converse effect to magnetostriction—has been predicted and observed in altermagnets, which are a special class of collinear antiferromagnets. In this talk, I will discuss our dilatometry and piezomagnetism results for non-collinear cousins of altermagnets, such as MnTe₂ and NiS₂. In particular, NiS₂ is found to display strong magnetostriction effects in both its antiferromagnetic and weak ferromagnetic states.