Changes in the Structural Parameters and Effective Magnetic Moment of Eu2−xCexCuO4+α−δ by Zn Substitution

Abstract

The effect of nonmagnetic Zn impurities on the structural parameters and effective magnetic moment of electron-doped superconducting cuprates Eu2−xCexCu1−yZnyO4+α−δ (ECCZO) with x = 0.10 and 0.15 and y = 0 and 0.01 has been investigated using XRD and SQUID measurements. From XRD measurements, it is found that the lattice parameter of c and the Cu-O bond length increase with increasing y. The crystallite size of ECCZO samples was relatively smaller than the sample without impurities determined by the Debye–Scherrer equation and the W-H Plot method. Changes in the lattice parameters of c and Cu-O bond length can affect the appearance of superconductivity (Tc). The smaller the value of the lattice parameter of c and the Cu-O bond length causes the distance between the conducting layer and the charge reservoir to be close enough so that the charge transfer process becomes easier. From the magnetic susceptibility measurement, paramagnetic characteristics were observed for samples with x = 0.10. Meanwhile, for samples with x = 0.15, diamagnetic characteristics can be identified in sample with y = 0. The onset of Tc was observed around 11 K, as indicated by a change from paramagnetic to diamagnetic characteristics. The superconductivity phase disappears with y = 0.01. The effective magnetic moments in samples with y = 0 are smaller than those in samples with y = 0.01. The effective magnetic moment in ECCZO can be contributed by Cu2+. When the amount of Cu2+ decreases due to the addition of nonmagnetic Zn2+ atoms, the overall effective magnetic moment value also decreases. Another possibility that causes a decrease in the value of the magnetic moment of the ECCZO is the existence of stripe-pinning model, which results in suppressed superconductivity by Zn.

Enhancement of magnetism by tailoring synthesis conditions in electron-doped superconducting nanoparticles

“…Among electron-doped cuprate superconductors, Eu 2Àx Ce x -CuO 4 is chosen because Eu 3+ does not have a calculated magnetic moment in the ground state. 11,33 It is important to remove the possibility that the spin fluctuations cannot be observed due to bigger effects from the magnetic moment of the A site. 34 The Ce concentration of 0.15 is chosen because it is an optimum doped concentration where the critical temperature is at its maximum.…”

“…34 The Ce concentration of 0.15 is chosen because it is an optimum doped concentration where the critical temperature is at its maximum. 11,33 Thus, it is expected that the suppression of superconductivity can be clarified. To synthesize the samples, a sol-gel method is chosen.…”

The Evaluation of the Crystal Structure and Magnetic Properties of Eu1.84Ce0.16CuO4+α−δ with Ni Substitution

“…All high-T c superconductor cuprates have the parent compounds of high-T c cuprates in common, and they are antiferromagnetic (AF). Studies on the mechanism of high-T c superconductor cuprates have been carried out [1][2][3][4][5][6][7][8]. Nonetheless, these studies have not obtained comprehensive results [9,10].…”

“…Hole-doped cuprate studies have been carried out to investigate the intrinsic properties of the material and the effect of impurities on superconductivity [2,3,6,7,11,12]. On the other hand, electron-doped cuprate studies have also succeeded in investigating the effects of magnetic and non-magnetic impurities on superconductivity [4,5]. Superconductor compounds (Nd, Pr, Sm, andEu) 2−x Ce x CuO 4 are formed when single-layer CuO 2 materials containing two atoms of rare earth elements, such as Nd, Pr, Sm, or Eu, are doped with Ce 4+ atoms.…”

“…Since Eu 3+ (4f 6 ) does not provide a magnetic moment in its ground state, the effect of impurities on superconductivity can be comprehensively studied [9]. When Eu 3+ is replaced by Ce 4+ , an additional electron is added to the CuO 2 plane, leading to the formation of the Eu 2−x Ce x CuO 4 (ECCO) system [1,4,5]. Moreover, due to the difficulty of controlling oxygen concentrations in materials, fewer research studies have been carried out on the impact of impurities on superconductivity in electron-doped cuprates [9,[13][14][15].…”