Heat capacities of (Ca,Ln)MnO3 (Ln=Pr, Nd and Sm)

Satoh, Hiroyuki; Embung, Eh; Mengang, Eh; Kamegashira, Naoki

doi:10.1016/j.jallcom.2004.12.116

Cited by 1 publication

(1 citation statement)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All the values of ΔH m are of hundreds of joules per mole, which are much smaller than the first-order structural phase transition enthalpy (3.36 kJ mol −1 ) of LaMnO 3 50 but close to the magnitude of the magnetic phase transition enthalpy of Ln 1−x Ae x MO 3 (Ln = Pr, Nd, Sm; Ae = Ca, Sr; M = Cr, Mn) with second-order nature. 53,54 The magnitude of ΔH m indicates the energetic barrier of the phase transition which helps to understand the thermodynamic stability during the process of IDPT. Consequently, it can be inferred by a comparison of ΔH m that the high-temperature structural phase of the Co sample exhibits a more stable thermodynamic state in comparison to that of the Ni sample.…”

Section: Resultsmentioning

confidence: 99%

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO₆ (M = Mn, Co, Ni)

et al. 2019

View full text Add to dashboard Cite

Lattice thermal expansion (LTE) has been investigated in double perovskites LaPbMSbO6 (M = Mn, Co, Ni). Ordinary LTE behavior with good thermal stability is identified for the Mn sample, whereas unusual LTE with a preferably expanded interplanar distance of (040) is revealed for Co and Ni samples. Temperature-dependent X-ray diffraction patterns (T-XRD), Raman spectra (T-Raman), and specific heat capacities (T-C p) consistently indicate that a rare isostructural displacive phase transition (IDPT) with a second-order phase transition nature is predominant near the critical temperature. Refinements of neutron powder diffraction (NPD) and in situ T-XRD data present temperature-sensitive bond parameters which are relevant to planar oxygen O1. X-ray photoelectron spectra (XPS) further confirm the Jahn–Teller (J-T) activated Co2+ (HS) or Ni3+ (HS/LS) cations at the B-site sublattice. This unusual LTE behavior could be understood by the cooperative J-T effect contributed by a Pb2+ ion and Co2+/Ni3+ ion from A- and B-site sublattices, respectively. The importance of 6s(Pb)-2p(O)-3d(Co/Ni) extended orbital hybridization on affecting thermal expansion behavior is highlighted on the basis of temperature-induced phonon mode softening. This study presents a microscopic description of connection between anisotropic thermal expansion and a cooperative J-T effect, which inspired exploration of thermal–mechanical coupled functional materials based on LaPbMSbO6 double perovskites.

show abstract

Section: Resultsmentioning

confidence: 99%

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO₆ (M = Mn, Co, Ni)

et al. 2019

View full text Add to dashboard Cite

show abstract

Heat capacities of (Ca,Ln)MnO3 (Ln=Pr, Nd and Sm)

Cited by 1 publication

References 18 publications

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO₆ (M = Mn, Co, Ni)

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO₆ (M = Mn, Co, Ni)

Contact Info

Product

Resources

About

Heat capacities of (Ca,Ln)MnO3 (Ln=Pr, Nd and Sm)

Cited by 1 publication

References 18 publications

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO6 (M = Mn, Co, Ni)

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO6 (M = Mn, Co, Ni)

Contact Info

Product

Resources

About

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO₆ (M = Mn, Co, Ni)

Connection between Unusual Lattice Thermal Expansion and Cooperative Jahn–Teller Effect in Double Perovskites LaPbMSbO₆ (M = Mn, Co, Ni)