Strain effects on superconducting and ferromagnetic transitions of ErRh₄B₄

Strain effects on T_c1 and T_c2 of ErRh₄B₄ of a primitive tetragonal phase have been investigated by shock-loading experiments for shock-pressures up to 90 GPa. The shock-loading introduces a large random strain into the sample, which is estimated as 0.006 for the sample shocked up to 90 GPa. From the ac susceptibility measurements, T_c1 and T_c2 have been found to decrease and increase with increasing shock-pressure, respectively. The former is considered to be due to crystalline disorder including residual random strain. The latter is understood as a result of residual random strain destroying the tetragonal symmetry.