CRITICAL BEHAVIOR IN La0.7Sr0.3Mn0.98Cu0.02O3 COMPOUND

  • Le Viet Bau
  • Trinh Thi Huyen

Tóm tắt

The magnetic data of La0.7Sr0.3Mn0.98Cu0.02O3 in the ferro-paramagnetic phase transition region has been analyzed using the Modified Arrott plots (MAP), the Kouvel-Fisher and the scaling hypothesis methods. The obtained data is compared to 4 theoretical models: Mean field, 3D Heisenberg, 3D Ising and Tritical mean field. The results suggest that the magnetic interaction in the sample is corresponding to the 3D Ising model. The n value (which relates to the magnetic order) conducted by law  is 0.641(8). This value is different from 0.556(5) derived from critical exponents of β and g  extracted from fitting values of spontaneous magnetisation and initial susceptibility to Kouvel-Fisher law. A low value of entropy is changed but the relative cooling power is improved.

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2020-11-23