Second harmonic measurement of the order parameter variation near the multicritical point of NH4Cl

G. Dolino , J. P. Pique , M. Vallade

Pressure variations of the order parameter η of NH4Cl are measured by second harmonic generation of light. The transition is continuous above 1.5 kbar; below, a phase coexistence is observed which may induce plastic deformations. Possible interpretations of the data with critical exponents and with the Landau theory are discussed.

Mots clés: ammonium compounds; critical points; optical harmonic generation; order disorder transformations; order parameter variation; multicritical point; NH sub 4 Cl; second harmonic generation; plastic deformations; Landau theory

Domaines: Articles anciens

G. Dolino, J. P. Pique, M. Vallade. Second harmonic measurement of the order parameter variation near the multicritical point of NH4Cl. Journal de Physique Lettres, 1979, 40 (13), pp.303-306. ⟨10.1051/jphyslet:019790040013030300⟩. ⟨jpa-00231629⟩