Structural, transport and optical properties of (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃nanocrystals: a wide band-gap magnetic semiconductor

Microstructural, Magnetic, and Optical Properties of Pr-Doped Perovskite Manganite La0.67Ca0.33MnO3 Nanoparticles Synthesized via Sol-Gel Process

“…The Raman peak around 224 cm − 1 can be assigned as A g (2), which is related to the tilting of MnO 6 octahedron, whereas the Raman peak around 425 cm − 1 is related to the Jahn-Teller type modes of the MnO 6 octahedron [33]. The Raman peak around 680 cm − 1 can be assigned as B 2g (1), which is related to the symmetric stretching vibration of oxygen in MnO 6 octahedron [33]. With increasing the Pr-doping concentration ( x ) up to x  = 0.4, the Raman peak around 680 cm − 1 disappeared, as shown in Fig.…”

“…Cao et al [32] studied the magnetic properties of La 0.67 − x Pr x Ca 0.33 MnO 3 ( x  = 0–0.67) synthesized by a conventional solid-state reaction, and found that the compounds underwent a ferromagnetic transition ( T C ) when the Pr-doping concentration ( x ) was below 0.4. Recently, Kumar et al [33] performed studies on the structural, transport, and optical properties of the (La 0.6 Pr 0.4 ) 0.65 Ca 0.35 MnO 3 nanoparticles post-annealed at different temperatures. The optical bandgaps of the (La 0.6 Pr 0.4 ) 0.65 Ca 0.35 MnO 3 nanoparticles were deduced from their UV-vis absorption spectra, which were found to be ∼ 3.5 eV.…”

Electronic structure study of wide band gap magnetic semiconductor (La0.6Pr0.4)0.65Ca0.35MnO3 nanocrystals in paramagnetic and ferromagnetic phases

“…These factors will affect the system in two opposite ways, which give rise to competition between these two factors. This competition does not allow systems to significantly change their transport behavior, and these systems remained semiconducting up to nearly 66-109 K. 21 The electronic states close to the Fermi-level govern the magnetic and electronic properties of the materials. Hence, the wide optical band-gap observed in (La 0.6 Pr 0.4 ) 0.65 Ca 0.35 MnO 3 (abbreviated as LPCMO) nanocrystals demands a detailed investigation of the electronic structures near the Fermi-level to better understand this behavior.…”

“…A recent study of (La 0.6 Pr 0.4 ) 0.65 Ca 0.35 MnO 3 (LPCMO) nanoparticles suggests improved application possibilities for manganite materials as wide band-gap magnetic semiconductors and optoelectronic materials due to the coexistence of three features: (1) a Curie temperature (T C ) around 200 K, (2) a metal-insulator transition around 66-109 K, depending on the particle size, and (3) an optical band-gap of around 3.4-3.5 eV. 21 Previously reported band-gaps for manganites are well below the band-gap observed in this system. 22,23 It is well-known that La 0.65 Ca 0.35 MnO 3 is a metallic ferromagnet below 265 K. 9,24 With doping of Pr-at the La-site, the behavior of the system changes from metallic to semiconductor, which might be due to induced charge-ordering of Mn 3þ and Mn 4þ .…”

“…The details of sample synthesis process and characterization results (structural, magnetic, transport, and optical properties) have been previously reported. 21 For the electronic structure study, the a)…”