Generalized Pippard Equations

Abstract

The Pippard equations for α, C_P, and β^T near a λ‐point transition have been generalized in terms of stress—strain variables. The resulting equations, which interrelate α_i, s_ij^T, and C_P near a λ point, are tested with data on quartz near its α—β transition. A consequence of the new equations is the prediction that C′=(c₁₁–c₁₂)/2 should be constant for cubic crystals near a λ point; this prediction is compared with experimental data on ammonium chloride.