  Time resolved pump and probe acoustics and first-principles calculations were
employed to assess elastic properties of the TbMnO3 perovskite manganite having
orthorhombic symmetry. Measuring sound velocities of bulk longitudinal and
shear acoustic waves propagating along at least two different directions in the
high symmetry planes (100), (010) and (001), provided a powerful mean to
selectively determine the six diagonal elastic constants C11= 227 GPa, C22= 349
GPa, C33= 274 GPa, C44= 71 GPa, C55= 57 GPa, C66= 62 GPa. Among the three
remaining off-diagonal ones, C23= 103 GPa was determined with a bissectrice
direction. Density functional theory calculations with colinear spin-polarized
provided complementary insights on their optical, elastic and magnetoelastic
properties.
