Anomalous variation ofA-type antiferromagnetic order and two-dimensional ferromagnetic fluctuation in orbital-orderedLa1−xEux

Orthorhombic distortion and novel magnetic phase separation in Pr0.5Eu0.5MnO3

“…The peak (T P ) in the ZFC-curve appears to be the Néel temperature (T N ). This is analogous to that observed in similar isovalent substitutions exhibiting A-type AFM ordering such as Eu 1Àx Y x MnO 3 , 3 La 1Àx Eu x MnO 3 , 6 and La 1Àx Gd x MnO 3 . 8 In the inset of Fig.…”

“…5 An A-type antiferromagnetic (AFM) order associated with a two-dimensional ferromagnetic (FM) short-range fluctuation was proposed in La 1Àx Eu x MnO 3 . 6 The decrease of the Néel temperature from 139 K for LaMnO 3 , to 91 K for La 0:5 Eu 0:5 MnO 3 , and down to 42 K for EuMnO 3 were correlated to the strong Jahn-Teller lattice distortion due to the decrease of ionic size. The A-site disorder is accompanied by inequalities in Mn-O bond lengths, a decrease in Mn-O-Mn bond angles, and the appearance of static Jahn-Teller distortion of the MnO 6 octahedra.…”

Heat capacity of EuMnO3 and Eu0.7A0.3MnO3 (A=Ca, Sr) compounds

“…The study of cohesive and thermal properties indicates that EuMnO 3 is more distorted than LaMnO 3 which is a parent compound of the family of oxides La 1Àx A x MnO 3 (A ¼ alkaline earth). This anomalous variation is due to the strong Jahn-Teller lattice distortion observed in EuMnO 3 [20]. The specific heat of Eu 0.7 Sr 0.3 MnO 3 and Eu 0.7 Ca 0.3 MnO 3 follows the same trend as that of the experimental curves [11] shown in Figs.…”

“…It is obvious from the earlier discussion that the agreement between the experimental [11][12][13][14][15][16][17][18][19][20] and the theoretical results on specific heat is reasonably good. This is not unexpected as we have taken into proper account the electronic specific heat term (g) ¼ 10 mJ mol À1 K À4 in our lattice specific heat term.…”

“…[11,14,20] for EuMnO 3 , Eu 0.7 A 0.3 MnO 3 (A ¼ Ca, Sr) compounds and VdW coefficient (c) ¼ 69.8 Â 10 À60 erg cm À6 calculated using SKV method [21], we have computed the model parameters (b) and (r) using Eqs. (3) and (4), as a function of temperature 5 KpTp100 K for EuMnO 3 , Eu 0.7 Sr 0.3 MnO 3 and Eu 0.7 Ca 0.3 MnO 3 and reported them in Tables 1-3, respectively.…”