Zdiri Feriel, Alonso José María, Mnasri Taoufik, de la Presa Patricia, Morales Irene, Martínez José Luis, Ben Younes Rached, Marin Pilar
Laboratory of Technology, Energy and Innovative Materials, Department of Physics, Faculty of Sciences of Gafsa, Gafsa 2112, Tunisia.
Instituto de Magnetismo Aplicado, Universidad Complutense de Madrid, A6 22,500 Km, Las Rozas, 28230 Madrid, Spain.
Materials (Basel). 2023 Feb 13;16(4):1573. doi: 10.3390/ma16041573.
We have investigated the structural, magnetic, and electrical transport properties of Pr Sr MnCo O nanopowders (x = 0, 0.05, 0.10 and 0.15). The Pechini Sol-gel method was used to synthesize these nanopowders. X-ray diffraction at room temperature shows that all the nano powders have an orthorhombic structure of Pnma space group crystallography. The average crystallite size of samples x = 0, 0.05, 0.10, and 0.15 are 33.78 nm, 29 nm, 33.61 nm, and 24.27 nm, respectively. Semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) confirms the expected stoichiometry of the sample. Magnetic measurements indicate that all samples show a ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. The Curie temperature T gradually decreases (300 K, 270 K, 250 K, and 235 K for x = 0, 0.05, 0.10, and 0.15, respectively) with increasing Co concentrations. The M-H curves for all compounds reveal the PM behavior at 300 K, while the FM behavior characterizes the magnetic hysteresis at low temperature (5 K). The electrical resistivity measurements show that all compounds exhibit metallic behavior at low temperature (T < Tρ) well fitted by the relation ρ = ρ + ρT + ρT and semiconductor behavior above Tρ (T > Tρ), for which the electronic transport can be explained by the variable range hopping model and the adiabatic small polaron hopping model. All samples have significant magnetoresistance (MR) values, even at room temperature. This presented research provides an innovative and practical approach to develop materials in several technological areas, such as ultra-high density magnetic recording and magneto resistive sensors.
我们研究了Pr Sr MnCo O纳米粉末（x = 0、0.05、0.10和0.15）的结构、磁性和电输运性质。采用佩琴尼溶胶-凝胶法合成这些纳米粉末。室温下的X射线衍射表明，所有纳米粉末均具有Pnma空间群晶体学的正交结构。样品x = 0、0.05、0.10和0.15的平均晶粒尺寸分别为33.78纳米、29纳米、33.61纳米和24.27纳米。通过能量色散光谱（EDS）进行的半定量化学分析证实了样品预期的化学计量比。磁性测量表明，所有样品均随着温度升高呈现铁磁（FM）到顺磁（PM）的转变。随着Co浓度增加，居里温度T逐渐降低（x = 0、0.05、0.10和0.15时分别为300 K、270 K、250 K和235 K）。所有化合物的M-H曲线在300 K时显示为顺磁行为，而在低温（5 K）时铁磁行为表现为磁滞。电阻率测量表明，所有化合物在低温（T < Tρ）下表现出金属行为，可用关系式ρ = ρ + ρT + ρT很好地拟合，在Tρ以上（T > Tρ）表现出半导体行为，其电子输运可用可变范围跳跃模型和绝热小极化子跳跃模型来解释。即使在室温下，所有样品也具有显著的磁电阻（MR）值。本研究为在超高密度磁记录和磁阻传感器等多个技术领域开发材料提供了一种创新且实用 的方法。
