A sprinkler device for delivering an irrigation liquid for gravity-based pivot or linear irrigation systems includes a support structure having a first portion with a nozzle defining a longitudinal axis for generating a jet of liquid, and a second portion with a baffle plate pivoted thereto and facing the nozzle. The second portion includes a drive system, which has a first magnet moving with a reciprocating oscillatory motion due to a negative pressure generated by the liquid that flows through the nozzle, and is configured to move the baffle plate along, and force it to pivot with a reciprocating oscillatory motion about the longitudinal axis through a predetermined angle, to thereby deliver the liquid over a sector area of the soil. A method of delivering an irrigation liquid for gravity-based pivot or linear irrigation systems that uses such a sprinkler device.