We report 105Pd nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) measurements on a single crystal of Ce3Pd20Si6, where antiferroquadrupolar and antiferromagnetic orders develop at low temperature. From the analysis of NQR and NMR spectra, we have determined the electric field gradient (EFG) tensors and the anisotropic Knight shift (K) components for both inequivalent Pd sites—Pd(32f) and Pd(48h). The observed EFG values are in excellent agreement with our state-of-the-art density functional theory calculations. The principal values of the quadrupolar coupling are MHz and MHz, for the Pd(32f) and Pd(48h) sites, respectively, which is large compared to the Larmor frequency defined by the gyromagnetic constant MHz/T for 105Pd. Therefore, the complete knowledge of K and the EFG tensors is crucial to establish the correspondence between NMR spectra and crystallographic sites, which is needed for a complete analysis of the magnetic structure, static spin susceptibility, and the spin-lattice relaxation rate data and a better understanding of the groundstate of Ce3Pd20Si6.
Structural, optical and electrical properties of Al+MoO3 and Au+MoO3 thin films prepared by simultaneous magnetron sputtering deposition were investigated. The influence of MoO3 sputtering power on the Al and Au nanoparticle formation and spatial distribution was explored. We demonstrated the formation of spatially arranged Au nanoparticles in the MoO3 matrix, while Al incorporates in the MoO3 matrix without nanoparticle formation. The dependence of the Au nanoparticle size and arrangement on the MoO3 sputtering power was established. The Al-based films show a decrease of overall absorption with an Al content increase, while the Au-based films have the opposite trend. The transport properties of the investigated films also are completely different. The resistivity of the Al-based films increases with the Al content, while it decreases with the Au content increase. The reason is a different transport mechanism that occurs in the films due to their different structural properties. The choice of the incorporated material (Al or Au) and its volume percentage in the MoO3 matrix enables the design of materials with desirable optical and electrical characteristics for a variety of applications.
We report 139 La nuclear magnetic resonance measurements on a single-crystal sample of La 1.875 Ba 0.125 CuO 4 under uniaxial stress. The spin order is shown to be more robust than at x = 0.115 doping, however, for magnetic field H in the c direction and the stress applied along the [110] direction (σ [110] ) the spin order transition temperature T SO is rapidly suppressed. This is in stark contrast to the behavior with stress in [100] direction (σ [100] ), which has virtually no effect on T SO . For H [110], σ [110] stress has a weakened effect, and the rate dT SO /dσ [110] is drastically reduced. Thus, H [110] acts as a stabilizing factor for spin-stripe order. Also, the onset temperature of the low-temperature tetragonal crystal structure T LTT is essentially unaffected by [110] stress, while it decreases slowly under compression along [100].We develop a Landau free energy model and interpret our findings as an interplay of symmetrybreaking terms driven by the orientation of spins. These findings put constraints on the applicability of theoretical models for the development of spin-stripe order.High-temperature superconductors present complex electronic behavior that has been the focus of intense research for almost four decades. One of the leading open questions is the relationship between competing electronic orders. Even though it has become clear that stripe charge order (CO) is ubiquitous in cuprates, the relationship between static charge and spin order (SO) remains incompletely understood. This is partly due to the limited number of systems in which both can be studied. The other reason is that the structural, electronic, and magnetic degrees of freedom are intertwined in these orders. Consequently, it remains a challenge to determine how they couple. In La 2−x Ba x CuO 4 (LBCO) close to x = 1/8 doping, CO becomes pinned as the symmetry of the lattice changes from low-temperature orthogonal (LTO) to low-temperature tetragonal (LTT) at T LTT = 57 K. At this doping, the SO transition temperature T SO reaches its maximum value [1-4] of ≈40 K, while the bulk superconducting transition temperature (T c ) is strongly suppressed. T c rapidly increases for doping away from 1/8, even though the structural transition and CO/SO persist. It was initially hypothesized that the LTT phase, in which the structural symmetry is locally lower than in the LTO phase, was necessary for CO/SO to condense. However, Hücker et al. [5] has shown in La 1.875 Ba 0.125 CuO 4 that hydrostatic pressure above ≈1.85 GPa suppresses the LTO/LTT transition while CO/SO survive, which indicated that the long-range LTT
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.