AbstractThe crystals of deuterated triglycine sulphate substituted with L‐alanine (LADTGS) were grown from nonpolar {001} growth sectors by four different methods.35 mol% of L‐alanine (LA) in the growth solution give a stable unipolarity of the crystals. A distribution of LA was measured by the electrical switching method using “hysteresis current” loops. A defect structure was observed in a microscope on the etched surface of crystals. Most uniform crystals have been obtained using an isothermal method without stirring of the growth so