Large Magnetovolume Effect in Yttrium Doped La-Ca-Mn-O Perovskite

Raman spectra in epitaxial thin films ofLa1−xCaxMnO3(Xiong1, Chen2, Wang3 et al. 2004Phys. Rev. B502232View full textAdd to dashboardCite

“…One is the rotational-like distortions of the M nO 6 octahedra due to the mismatch between the averaged ionic radii r A of the A-site species and the ionic radius r Mn of Mn. It is one of the strain effects induced by chemical pressure 17,18 . The other is JT distortions of M n 3+ O 6 octahedra.…”

Effect of heavy cation doping on thermal properties of LaMnO3

“…The value of Grüneisen parameter seems to be correct since its value lies between 2 and 3 as reported earlier [22]. It is to be noted that the higher value of Debye temperature indicate the higher phonon frequencies of La 0.25 Ca 0.75 MnO 3 . These values are compared with the calculated and experimental values [19][20][21][22] of the parent compound LaMnO 3 in Table 2 to indicate the large effect of heavy doping on the thermal properties of LaMnO 3 .…”

“…Although both the compounds are perovskites; but LaMnO 3 consists of the deformed MnO 3 octahedra (due to Jahn-Teller Effect), whereas the octahedra are perfect in CaMnO 3 . In case of Ca doping in LaMnO 3 , following the Goldschmidt's tolerance factor, the replacement of La 3+ (ionic radius r = 1.03 Å) by Ca 2+ (r = 0.99 Å) leads to the stabilization of the orthorhombic structure at higher temperatures [3] but the structure of La 0.25 Ca 0.75 MnO 3 is highly distorted within Pnma space symmetry [4,5]. The high strain energy of this compound can be attributed to the cubic structure of CaMnO 3 adjusting in the orthorhombic setting of LaMnO 3 .…”

“…In case of Ca doping in LaMnO 3 , following the Goldschmidt's tolerance factor, the replacement of La 3+ (ionic radius r = 1.03 Å) by Ca 2+ (r = 0.99 Å) leads to the stabilization of the orthorhombic structure at higher temperatures [3] but the structure of La 0.25 Ca 0.75 MnO 3 is highly distorted within Pnma space symmetry [4,5]. The high strain energy of this compound can be attributed to the cubic structure of CaMnO 3 adjusting in the orthorhombic setting of LaMnO 3 . In very heavily doped compounds (x > 0.75) the competition between the two structures may result in charge ordered layers of cubic CaMnO 3 alternating with strained LaMnO 3 layer [7].…”

Magnetocaloric effect in La1-x Ce x MnO3

“…Some perovskite manganites exhibit discontinuous variation in volume at the ferromagnetic transition and an associated sharp change in magnetization [18,19]. The simultaneous discontinuous volume variation and magnetic transition at C T can strongly influence the magnetic entropy change.…”