sentences:  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.