EN
The aim of the present work was to study the phase transition in the LaFe_{11.14}Co_{0.66}Si_{1.1}M_{0.1} (where M = Al or Ga) alloys. Research was carried out using field dependences of magnetization measured at a wide temperature range. Positive slope of the Arrott plots showed that magnetic phase transition in both investigated samples was of second order nature. The temperature dependences of the Landau coefficients also revealed second order phase transition in both specimens. The analysis carried out using universal curve confirmed second nature of phase transition in both samples.