Structural, electronic, and magnetic entropy contributions of the orbital order-disorder transition in LaMnO3

Autor(es)

Ramirez, F. E. N. ^[1] ; Cunha, B. B. ^[1] ; Alves, W. A. ^[1] ; Jardim, R. F. ^[2] ; Muccillo, R. ^[3] ; Souza, J. A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, SP - Brazil

^[2] Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo - Brazil

^[3] IPEN CNEN SP, BR-05422970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PHASE TRANSITIONS; v. 84, n. 3, p. 284-290, 2011.
• Citações Web of Science: 1

Resumo

Measurements of X-ray diffraction, electrical resistivity, and magnetization are reported across the Jahn-Teller phase transition in LaMnO(3). Using a thermodynamic equation, we obtained the pressure derivative of the critical temperature (T(JT)), dT(JT)/dP = -28.3 K GPa(-1). This approach also reveals that 5.7(3)J(mol K)(-1) comes from the volume change and 0.8(2)J(mol K)(-1) from the magnetic exchange interaction change across the phase transition. Around T(JT), a robust increase in the electrical conductivity takes place and the electronic entropy change, which is assumed to be negligible for the majority of electronic systems, was found to be 1.8(3)J(mol K)(-1). (AU)

• Processo FAPESP: 05/53241-9 - Estudo de fenômenos intergranulares em materiais cerâmicos
• Beneficiário: Reginaldo Muccillo
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 07/01039-7 - Estudo do comportamento critico de transicoes de fase em sistemas com propriedades magneticas, eletronicas e estruturais fortemente correlacionadas.
• Beneficiário: José Antonio Souza
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado