Scholarlink

<p>Chemical doping, external pressure, and oxygen stoichiometry are known to modulate the interplay between charge, spin, orbital, and lattice degrees of freedom in manganites, thereby altering both their electronic and crystallographic structures. In this study, we investigate the magnetotransport and magnetic properties of La₀.₆Ca₀.₄MnO₃ (LCMO) and La₀.₆Sr₀.₄MnO₃ (LSMO) thin films fabricated via RF magnetron sputtering onto single-crystal substrates. The films, each with a nominal thickness of ~ 7&#xa0;nm, were deposited on (001) Nb-doped SrTiO₃ (designated LCMO-S and LSMO-S), while LSMO was also grown on (110) NdGaO₃ substrates (LSMO-N) to introduce distinct epitaxial strain conditions. Atomic force microscopy revealed atomically smooth surfaces with step-terrace morphologies, and X-ray diffraction confirmed high-quality epitaxial growth without secondary phases. Current–voltage (I–V) measurements exhibited strong correlations between curve linearity and the metal–insulator transition (MIT), consistent with nanoscale phase separation comprising coexisting metallic and insulating regions. This intrinsic inhomogeneity is a characteristic signature of mixed-valence manganites and persists under a range of thermal and magnetic field conditions. Magnetization data acquired via SQUID magnetometry, fitted with the Langevin function, indicate the onset of a ferromagnetic state at 220&#xa0;K under an external magnetic field of 2 T. Notably, in this temperature regime, the I–V response approaches linearity, suggesting the emergence of a high-temperature ferromagnetic insulating phase. These findings underscore the persistence of electronic phase separation even at low temperatures and in strong magnetic fields. The study highlights the critical role of strain, dimensionality, and substrate orientation in governing the magnetoelectronic landscape of manganite thin films. The observed properties render these systems promising for advanced applications in magnetoresistive sensors, thermoelectric modules, multifunctional oxide electronics, and magnetocaloric technologies.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Understanding the electronic phase separation in La0.6A0.4MnO3 (A = Ca and Sr) thin films at low temperature and high magnetic fields

  • 期刊论文

  • 发表日期：

    2025年8月11日

查看全文
  • Aradhana Kumari,
  • Asokan Kandasami,
  • Vijay Raj Singh

摘要

Chemical doping, external pressure, and oxygen stoichiometry are known to modulate the interplay between charge, spin, orbital, and lattice degrees of freedom in manganites, thereby altering both their electronic and crystallographic structures. In this study, we investigate the magnetotransport and magnetic properties of La₀.₆Ca₀.₄MnO₃ (LCMO) and La₀.₆Sr₀.₄MnO₃ (LSMO) thin films fabricated via RF magnetron sputtering onto single-crystal substrates. The films, each with a nominal thickness of ~ 7 nm, were deposited on (001) Nb-doped SrTiO₃ (designated LCMO-S and LSMO-S), while LSMO was also grown on (110) NdGaO₃ substrates (LSMO-N) to introduce distinct epitaxial strain conditions. Atomic force microscopy revealed atomically smooth surfaces with step-terrace morphologies, and X-ray diffraction confirmed high-quality epitaxial growth without secondary phases. Current–voltage (I–V) measurements exhibited strong correlations between curve linearity and the metal–insulator transition (MIT), consistent with nanoscale phase separation comprising coexisting metallic and insulating regions. This intrinsic inhomogeneity is a characteristic signature of mixed-valence manganites and persists under a range of thermal and magnetic field conditions. Magnetization data acquired via SQUID magnetometry, fitted with the Langevin function, indicate the onset of a ferromagnetic state at 220 K under an external magnetic field of 2 T. Notably, in this temperature regime, the I–V response approaches linearity, suggesting the emergence of a high-temperature ferromagnetic insulating phase. These findings underscore the persistence of electronic phase separation even at low temperatures and in strong magnetic fields. The study highlights the critical role of strain, dimensionality, and substrate orientation in governing the magnetoelectronic landscape of manganite thin films. The observed properties render these systems promising for advanced applications in magnetoresistive sensors, thermoelectric modules, multifunctional oxide electronics, and magnetocaloric technologies.