Piezomagnetism

Piezomagnetism is a phenomenon observed in some antiferromagnetic crystals. It is characterised by a linear coupling between the system's magnetic polarisation and mechanical strain. In a piezomagnetic material, one may induce a spontaneous magnetic moment by applying physical stress, or a physical deformation by applying a magnetic field.

Piezomagnetism differs from the related property of magnetostriction; if an applied magnetic field is reversed in direction, the strain produced changes signs. Additionally, a non-zero piezomagnetic moment can be produced by mechanical strain alone, at zero field, which is not true of magnetostriction.[1] According to IEEE: "Piezomagnetism is the linear magnetomechanical effect analogous to the linear electromechanical effect of piezoelectricity. Similarly, magnetostriction and electrostriction are analogous second-order effects. These higher-order effects can be represented as effectively first-order when variations in the system parameters are small compared with the initial values of the parameters".[2]

The piezomagnetic effect is made possible by an absence of certain symmetry elements in a crystal structure; specifically, symmetry under time reversal forbids the property.[3]

The first experimental observation of piezomagnetism was made in 1960, in the fluorides of cobalt and manganese.[4]

The strongest piezomagnet known is uranium dioxide, with magnetoelastic memory switching at magnetic fields near 180,000 Oe.[5]

References
  1. B. D. Cullity (1971), Fundamentals of magnetostriction. Journal of Metals 1, 323.
  2. IEEE Std 319-1990 (1991), IEEE Standard on Magnetostrictive Materials: Piezomagnetic Nomenclature.
  3. I. E. Dzialoshinskii (1958), The problem of piezomagnetism. Soviet Phys. JETP 6, 621.
  4. A.S. Borovik-Romanov (1960), Piezomagnetism in the antiferromagnetic fluorides of cobalt and manganese. Soviet Phys. JETP 11, 786.
  5. M. Jaime et al. (2017), Piezomagnetism and magnetoelastic memory in uranium dioxide. Nature Communications 8, 99.
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